feat: add unknown-rendition baseline planning for Terminal 1.18

CHANGELOG.md

@@ -2,6 +2,21 @@
 
 Notable changes to `Icod.Terminal` are recorded here for consumers who need a concise release history. Detailed design evidence remains in the versioned roadmaps, tranche records, and public-API baseline documents.
 
+## 1.18.0
+
+### Unknown-rendition baseline recovery
+
+- Adds `TerminalScreenPlanner.PlanRenditionBaseline()` for safe recovery from unknown physical rendition state without requiring a caller-supplied known current rendition.
+- Derives obligations from raw attribute-entry and color-selection evidence; returns `null` when any exposed axis cannot be restored unconditionally.
+- Emits global attribute reset or every required safe specific exit in stable order, then restores original colors.
+- Preserves valid zero-byte planning for empty and reset-only profiles while retaining exact byte cost, padding, affected-line, same-session ownership, stale-epoch, cancellation, and transaction semantics.
+- Exposes no TermInfo type or raw capability/terminal-string API and leaves retained screen/layout/damage policy above Terminal.
+- Finalizes identical `net8.0`/`net9.0`/`net10.0` public API snapshots with fingerprint `48975f2c42f6c544e9c574a9b3d79f7e2b7b3ecb10ab1a5a0b7067749e38e65d`.
+- Retains production dependencies `Icod.TermInfo 1.15.0` and `Icod.Timing 1.0.0`.
+- Qualifies fresh package consumers, published `Icod.DCurses 1.6.0` compatibility, and a separate TermInfo-free future-renderer package consumer on all target frameworks.
+
+See `docs/releases/1.18.0.md`, `docs/Public-API-Baseline-1.18.md`, and `Icod.Terminal-1.18.0-Development-Roadmap.md` for the complete contract.
+
 ## 1.17.1
 
 ### Packaged README and release metadata correction

Directory.Build.props

@@ -1,7 +1,7 @@
 <Project>
 	<PropertyGroup>
 		<!-- Repository-wide release version authority. -->
-		<VersionPrefix>1.17.1</VersionPrefix>
+		<VersionPrefix>1.18.0</VersionPrefix>
 		<VersionSuffix></VersionSuffix>
 		<Version Condition="'$(VersionSuffix)' == ''">$(VersionPrefix)</Version>
 		<Version Condition="'$(VersionSuffix)' != ''">$(VersionPrefix)-$(VersionSuffix)</Version>

Icod.Terminal-1.18.0-Development-Roadmap.md

@@ -0,0 +1,173 @@
+# Icod.Terminal 1.18.0 Development Roadmap
+
+**Release:** `1.18.0`
+**Theme:** Unknown-rendition baseline recovery for Terminal-only screen consumers
+**Status:** T180-T185 accepted; stable `1.18.0` candidate qualified
+**Candidate identity:** `1.18.0`
+**Stable compatibility floor:** `1.0.0`
+**Current published line:** `1.17.0`; `1.17.1` is the documentation-only patch baseline
+
+## Release objective
+
+Version 1.18 closes the single Terminal contract gap found by the `Icod.DCurses 2.0` decoupling readiness gate. A renderer that does not know the terminal's physical rendition state must be able to request one safe, opaque plan that restores every rendition axis exposed by the selected profile's enter/select evidence.
+
+The governing rule is:
+
+> Terminal may claim a rendition baseline only when it can unconditionally restore every rendition axis exposed by the selected profile that Terminal can enter or select; otherwise no plan is available.
+
+The dependency direction remains:
+
+```text
+Icod.DCurses -> Icod.Terminal -> Icod.TermInfo
+```
+
+`Icod.TermInfo` remains Terminal's private capability-data, expansion, padding, and cost authority. No TermInfo type, capability identifier, terminal string, or expansion program enters the new public contract.
+
+## Design and implementation authorities
+
+- [`docs/superpowers/specs/2026-09-18-1.18.0-rendition-baseline-design.md`](docs/superpowers/specs/2026-09-18-1.18.0-rendition-baseline-design.md)
+- [`docs/superpowers/plans/2026-09-18-1.18.0-rendition-baseline.md`](docs/superpowers/plans/2026-09-18-1.18.0-rendition-baseline.md)
+- [`Icod.DCurses 2.0 PR #32`](https://github.com/uniblab/Icod.DCurses/pull/32)
+
+## Accepted implementation record
+
+T180-T185 are complete on PR #63. The implementation adds only `PlanRenditionBaseline()` to the public surface and retains production `Icod.TermInfo 1.15.0` / `Icod.Timing 1.0.0`.
+
+- T180 recorded the `CS1061` package/source RED witness before the method existed.
+- T181 implemented unknown-state restoration with all-or-nothing availability.
+- T182 qualified attribute-only, color-only, combined, specific-exit, unsafe, empty, reset-only, padding, deterministic, and side-effect-free behavior.
+- T183 qualified same-session ordering, foreign-session rejection, stale output epochs, and pre-commit cancellation.
+- T184 froze identical API snapshots at `48975f2c42f6c544e9c574a9b3d79f7e2b7b3ecb10ab1a5a0b7067749e38e65d`, verified the deliberate mismatch rejection, and passed the candidate package, XML, dependency, published DCurses 1.6.0, and TermInfo-free future-renderer consumers across all three target frameworks.
+- T185 finalized stable package identity and release-facing metadata, then qualified the stable candidate at commit `56bbc011325e5c88e67f243a9b882b97bae9aac7` in workflow run `35382158657`.
+
+The retained DCurses PR #32 package witness remains governed by its published-package resume criterion. It resumes after `Icod.Terminal 1.18.0` is published; no unpublished project reference or raw TermInfo workaround is introduced.
+
+## Stable-candidate qualification
+
+Workflow run [`35382158657`](https://github.com/uniblab/Icod.Terminal/actions/runs/35382158657) passed all nine jobs at source head `56bbc011325e5c88e67f243a9b882b97bae9aac7`: Windows, Linux, macOS, package candidate, Foundation, Presentation, Semantic and hardening, Stable 1.x release line, and validated package artifact.
+
+- Unit tests: 2,383 passed, zero failed, on each of `net8.0`, `net9.0`, and `net10.0`.
+- TermInfo integration tests: 15 passed, zero failed, on each target framework.
+- Stable package: `Icod.Terminal.1.18.0.nupkg`, SHA-256 `e8f2b374fd0865aa151910686197096b344f7daf8d0ef72331520d944b322932`.
+- Symbols package: `Icod.Terminal.1.18.0.snupkg`, SHA-256 `8a14d163f2ea0bf030bea0416e0a84a919a2e8c83c692956b3a2a98470d78422`.
+- Candidate artifact: ID `10563191796`, uploaded ZIP SHA-256 `b0fc9e57dcd0ccf42befc7d8d6fe91e9b0e19b62691fbfb775164252147fa028`.
+- Validated artifact: ID `10562732859`, uploaded ZIP SHA-256 `1ddf8f76fbb6131271dd9123d5cab8043ddc68fd0084dfc1d1e84e8916121537`.
+- Public API: identical on all target frameworks, SHA-256 `48975f2c42f6c544e9c574a9b3d79f7e2b7b3ecb10ab1a5a0b7067749e38e65d`.
+- Package consumers: stable 1.x smoke, published `Icod.DCurses 1.6.0` soak, and the TermInfo-free future-renderer screen-contract witness passed on all target frameworks.
+
+## Public contract
+
+Add one method to the existing session-bound planner:
+
+```csharp
+public TerminalScreenOperationPlan? PlanRenditionBaseline();
+```
+
+The method represents an unknown physical rendition, not a known current `TerminalScreenRendition`. It is side-effect free and returns an opaque `Rendition` plan owned by the same planner/session.
+
+The returned plan:
+
+- restores all enterable text attributes to their normalized default through a global reset or a complete stable sequence of safe specific exits;
+- restores foreground and background colors to terminal defaults whenever Terminal can select colors;
+- emits the global attribute reset before original-color restoration;
+- includes capability expansion, padding, exact encoded-byte cost, and affected-line accounting;
+- remains valid only through the existing same-session transaction ownership rules.
+
+The method returns `null` if any profile-exposed enterable/selectable rendition axis cannot be restored safely from an unknown state. This obligation is computed from entry/selection evidence before current normalization suppresses unsafe requests. A valid zero-byte plan is allowed only when the profile exposes no enterable attribute and no selectable color axis; reset capabilities alone do not create reachable state.
+
+Existing `PlanRenditionTransition(...)`, `PlanRenditionReset(current)`, normalization, operation-plan opacity, and transaction semantics remain unchanged.
+
+## Tranche sequence
+
+```text
+T180  contract freeze, reference snapshot, API-regret gate, and alpha identity
+T181  unknown-state rendition-baseline planner and focused red-green tests
+T182  capability ordering, padding, cost, zero-byte, and nullability hardening
+T183  session ownership, transaction commitment, and adversarial qualification
+T184  package/API/XML/docs and DCurses 2.0 package-only acceptance
+T185  release-candidate qualification and stable 1.18.0 closure
+```
+
+## T180 — Contract freeze and development identity
+
+Record the 1.17.1 baseline, establish `1.18.0-alpha.1`, and freeze the single additive public signature and its XML contract before implementation.
+
+Acceptance requires:
+
+- no change to existing 1.x signatures or behavior;
+- no raw TermInfo or escape-sequence exposure;
+- explicit distinction between unknown physical state and known-current reset;
+- exact profile-evidence, safety, nullability, ordering, ownership, and zero-byte rules;
+- a package-level failing witness matching the DCurses T2001 blocker, with representative enter/select capabilities added to its synthetic profile so the `<sgr0><op>` expectation is semantically reachable.
+
+## T181 — Baseline planner
+
+Implement `PlanRenditionBaseline()` in `TerminalScreenPlanner` using existing private capability interpretation and opaque plan construction.
+
+Acceptance covers:
+
+- attribute-only profiles using global attribute reset;
+- multi-attribute profiles without a global reset using every required safe specific exit in stable order;
+- color-only profiles using original-color-pair restoration;
+- combined profiles emitting attribute reset before color restoration;
+- correct `Rendition` kind and one affected line;
+- side-effect-free planning followed by exact-byte transaction commitment.
+
+## T182 — Safety and cost hardening
+
+Prove that availability describes unconditional recovery rather than a best-effort partial reset.
+
+Acceptance covers:
+
+- `null` when any enterable attribute lacks both a global reset and a safe specific exit;
+- complete specific-exit coverage and stable underline, standout, italic, then strikeout ordering when no global reset exists;
+- `null` when foreground or background selection is available without original-color-pair restoration;
+- a zero-byte plan only for a profile with no enterable attribute and no selectable color axis, including a reset-only profile;
+- exact padding-sensitive byte cost after capability expansion;
+- deterministic segment ordering, overflow safety, and repeated-call stability;
+- no dependence on a caller-supplied or retained physical rendition state.
+
+## T183 — Ownership and transaction qualification
+
+Exercise the new plan through the existing transaction boundary without inventing another output or state domain.
+
+Acceptance covers same-session commitment, foreign-session rejection, stale-epoch rejection, cancellation before commitment, serialized output, and unchanged cleanup/failure behavior. Planning itself must perform no writes, flushes, epoch changes, or lifecycle mutation.
+
+## T184 — Package and downstream acceptance
+
+Freeze identical public API/XML snapshots for `net8.0`, `net9.0`, and `net10.0`; update the active baseline selector, package smoke, and the local future-DCurses compile/package consumer. That local consumer and the eventual DCurses production boundary must have no direct `Icod.TermInfo` reference. Separately, compile and run the DCurses T2001 exact-byte witness against the candidate package using its already reviewed test-only TermInfo fixture exception. The retained downstream witness's synthetic profile must add representative enter/select capabilities before it can truthfully expect `<sgr0><op>`; its public API call, transaction path, and exact-byte assertion remain unchanged.
+
+Published `Icod.DCurses 1.6.0` compatibility remains a separate required witness. Production dependencies remain `Icod.TermInfo 1.15.0` and `Icod.Timing 1.0.0` unless an independently justified qualification issue requires a later reviewed change.
+
+## T185 — Stable closure
+
+Complete cross-platform, package, public-API, XML-documentation, dependency, security, and exact-head artifact qualification. Synchronize README, changelog, compatibility authority, release notes, and the main roadmap.
+
+Tagging, release creation, and publication remain explicit maintainer actions after the stable candidate is accepted.
+
+Current closure work removes the prerelease suffix, synchronizes consumer/release/architecture/security documentation, runs the complete exact-head workflow, records its artifact/test evidence, and stops before merge, tag, GitHub Release, or publication.
+
+## Explicit non-goals
+
+Version 1.18 does not add:
+
+- retained physical rendition state or automatic state tracking;
+- desired-versus-physical screen comparison or repaint policy;
+- Terminal-owned cells, windows, layout, clipping, damage, or Unicode width;
+- public raw capabilities, terminal strings, or generic control-sequence builders;
+- a replacement for `PlanRenditionReset(current)`;
+- transaction, output-epoch, hyperlink, raster, input, query, or lifecycle redesign;
+- new raster-animation, PTY, process-hosting, or widget features;
+- a production dependency update without separate evidence and review.
+
+## Release gates
+
+The stable candidate must pass:
+
+- focused red-green exact-byte rendition-baseline tests;
+- the full unit and TermInfo-integration suites on all target frameworks;
+- Windows, Linux, and macOS workflow matrices;
+- package/public API/XML/license validation;
+- fresh package-only screen-contract and DCurses 2.0 readiness consumers;
+- published DCurses 1.6 compatibility and hardening;
+- exact-head artifact and independent review gates.

Icod.Terminal-Development-Roadmap.md

@@ -6,7 +6,8 @@
 - **Target frameworks:** `net8.0`; `net9.0`; `net10.0`
 - **Current published feature line:** `1.17.0` — Terminal-owned Screen Output Contracts
 - **Current patch line:** `1.17.1` — Packaged README and release metadata correction
-- **Development status:** 1.17.0 published; 1.17.1 documentation-only patch in qualification
+- **Development status:** 1.17.1 published; 1.18.0 stable candidate qualified on PR #63
+- **Active development target:** `1.18.0` — Unknown-rendition baseline recovery for Terminal-only screen consumers
 - **Stable compatibility floor:** `1.0.0`
 
 ## Purpose
@@ -23,6 +24,8 @@ The published feature line uses production `Icod.TermInfo 1.15.0` and optional t
 
 Version 1.17.1 is a documentation-only patch that corrects the README embedded in 1.17.0 and synchronizes release metadata. It makes no runtime or public-API change.
 
+Version 1.18.0 is a qualified stable source candidate on PR #63. T180-T185 are accepted: the additive unknown-rendition baseline API, hardening/ownership tests, identical three-framework API fingerprint, package/XML gates, published DCurses 1.6.0 soak, TermInfo-free future-renderer package witness, and nine-job stable-candidate workflow are complete. Merge, tag, release creation, and publication remain maintainer actions.
+
 ## Current architecture
 
 ```text
@@ -71,12 +74,13 @@ Optional integration tests/samples may use `Icod.TermInfo.Inspection 1.15.0`; In
 1.16.0  persistent raster animation and frame lifecycle             PUBLISHED
 1.17.0  Terminal-owned dimensions, screen planning, and transactions PUBLISHED
 1.17.1  packaged README and release metadata correction             PATCH
+1.18.0  unknown-rendition baseline recovery                         CANDIDATE
 ```
 
-The final 1.17 public API fingerprint is:
+The 1.18 public API fingerprint is:
 
 ```text
-c0a051a925d551e526343ef59d8c47d75e41868d84235fa30bfa7debe1b3ceb9
+48975f2c42f6c544e9c574a9b3d79f7e2b7b3ecb10ab1a5a0b7067749e38e65d
 ```
 
 Permanent ownership authority: [`docs/Persistent-Raster-Ownership.md`](docs/Persistent-Raster-Ownership.md).
@@ -212,8 +216,44 @@ Authorities:
 - [`docs/superpowers/specs/2026-09-17-1.17.0-terminal-screen-output-design.md`](docs/superpowers/specs/2026-09-17-1.17.0-terminal-screen-output-design.md)
 - [`docs/superpowers/plans/2026-09-17-1.17.0-terminal-screen-output.md`](docs/superpowers/plans/2026-09-17-1.17.0-terminal-screen-output.md)
 
+## 1.18 development line — Unknown-rendition Baseline Recovery
+
+Version 1.18 is a focused additive release that closes the sole blocking Terminal contract found by the DCurses 2.0 readiness gate.
+
+The governing rule is:
+
+> Terminal may claim a rendition baseline only when it can unconditionally restore every rendition axis exposed by the selected profile that Terminal can enter; otherwise no plan is available.
+
+The release adds one public planner method:
+
+```csharp
+public TerminalScreenOperationPlan? PlanRenditionBaseline();
+```
+
+The plan represents unknown physical rendition state, restores attributes before original colors in a safe deterministic order, retains Terminal-owned expansion/padding/cost and same-session transaction ownership, and returns a valid zero-byte plan only when the selected profile exposes no enterable attribute and no selectable color axis. Existing known-state reset and transition behavior remains unchanged.
+
+T180-T185 are accepted. The stable candidate at `56bbc011325e5c88e67f243a9b882b97bae9aac7` passed the complete Windows/Linux/macOS, package, API/XML, downstream, and artifact matrix in workflow run `35382158657`. Publication remains a separate maintainer action.
+
+The tranche sequence is:
+
+```text
+T180  contract freeze, reference snapshot, API-regret gate, and alpha identity
+T181  unknown-state rendition-baseline planner and focused red-green tests
+T182  capability ordering, padding, cost, zero-byte, and nullability hardening
+T183  session ownership, transaction commitment, and adversarial qualification
+T184  package/API/XML/docs and DCurses 2.0 package-only acceptance
+T185  release-candidate qualification and stable 1.18.0 closure
+```
+
+Authorities:
+
+- [`Icod.Terminal-1.18.0-Development-Roadmap.md`](Icod.Terminal-1.18.0-Development-Roadmap.md)
+- [`docs/superpowers/specs/2026-09-18-1.18.0-rendition-baseline-design.md`](docs/superpowers/specs/2026-09-18-1.18.0-rendition-baseline-design.md)
+- [`docs/superpowers/plans/2026-09-18-1.18.0-rendition-baseline.md`](docs/superpowers/plans/2026-09-18-1.18.0-rendition-baseline.md)
+- [`Icod.DCurses 2.0 PR #32`](https://github.com/uniblab/Icod.DCurses/pull/32)
+
 ## Later development candidates
 
-After 1.17, independent candidates still include animation-frame composition, absolute screen-coordinate placement, pixel-within-cell positioning, richer terminal-side reconciliation only if a truthful non-destructive primitive exists, image-file decoding/transcoding, and PTY/ConPTY process hosting.
+After 1.18, independent candidates still include animation-frame composition, absolute screen-coordinate placement, pixel-within-cell positioning, richer terminal-side reconciliation only if a truthful non-destructive primitive exists, image-file decoding/transcoding, and PTY/ConPTY process hosting.
 
 Scene/window/cell ownership and hidden source-raster replay caches remain intentionally outside the Terminal contract.

Icod.Terminal.csproj

@@ -39,7 +39,7 @@
 		<Title>Icod.Terminal</Title>
 		<Authors>Timothy J. Bruce</Authors>
 		<Description>Managed, cross-platform live-terminal session, endpoint, mode, input, lifecycle, and terminal-control foundation for .NET.</Description>
-		<PackageReleaseNotes>Icod.Terminal 1.17.1 corrects the packaged README and release metadata for the published 1.17 line without changing the runtime or public API. Release notes: https://github.com/uniblab/Icod.Terminal/blob/main/docs/releases/1.17.1.md. Compatibility policy: https://github.com/uniblab/Icod.Terminal/blob/main/docs/Compatibility-and-Versioning.md.</PackageReleaseNotes>
+		<PackageReleaseNotes>Icod.Terminal 1.18.0 adds safe unknown-rendition baseline planning for Terminal-only screen consumers. Release notes: https://github.com/uniblab/Icod.Terminal/blob/main/docs/releases/1.18.0.md. Compatibility policy: https://github.com/uniblab/Icod.Terminal/blob/main/docs/Compatibility-and-Versioning.md.</PackageReleaseNotes>
 		<PackageReadmeFile>README.md</PackageReadmeFile>
 		<PackageIcon>icon.png</PackageIcon>
 		<PackageProjectUrl>https://github.com/uniblab/Icod.Terminal</PackageProjectUrl>