Prepare Icod.Terminal 1.17.1 README correction

[uniblab]

Summary

Prepares Icod.Terminal 1.17.1 as a documentation-only patch correcting the stale README that shipped inside 1.17.0.

The patch contains no runtime or public-API changes. Production dependencies remain Icod.TermInfo 1.15.0 and Icod.Timing 1.0.0.

Corrections

• identifies 1.17.1 as the stable release documented by the package
• updates the installation command to Icod.Terminal 1.17.1
• removes obsolete candidate, merge, tagging, and publication language
• distinguishes the published Icod.DCurses 1.6.0 graph from the intended Terminal-only Icod.DCurses 2.0 dependency boundary
• adds a compact example of Profile, GetDimensions(), side-effect-free screen planning, and session-bound transaction commitment
• synchronizes package metadata, changelog, curated release notes, compatibility guidance, and the main roadmap

Regression prevention

packaging/VerifyReleaseLinePackage.ps1 now requires exactly one anchored stable-release line and one explicit installation command, verifies that both versions match the package version, and rejects candidate/pre-publication language in the packed README.

The checks use APIs compatible with Windows PowerShell 5.1.

Compatibility

• no source, binary, runtime, behavioral, or public-API change from 1.17.0
• public API fingerprint remains c0a051a925d551e526343ef59d8c47d75e41868d84235fa30bfa7debe1b3ceb9
• targets remain net8.0, net9.0, and net10.0
• production dependencies remain Icod.TermInfo 1.15.0 and Icod.Timing 1.0.0

Verification

• exact branch tree matches independently reviewed local tree 1478f3e8ff516c78c808c56f2adc20f237a94e10
• release-documentation assertions and git diff --check pass locally
• no src/ or test-source files changed
• independent review found no Critical, Important, or Minor findings
• exact-head pull-request workflow #1985 / run 35364339320 passes all nine jobs
• maintainer merge, tag, release, and publication decision

Exact-head workflow #1985 is the authoritative build, package, PowerShell, and cross-platform execution gate; all nine jobs passed.

This PR does not merge, tag, create a release, or publish packages.