feat(rate): add canonical regional plan file I/O

docs/release/rate_of_closure_campaign.v1.json

@@ -134,7 +134,7 @@
       "pr": 4282,
       "branch": "feat/4199-wind-workflow",
       "base_branch": "feat/4199-wind-scalar-adapter",
-      "head_sha": "b2baf6ef615b0d756a86ac4ca7eef2fc583210ee",
+      "head_sha": "18fe89201d657116bbca99922297c14968356c44",
       "state": "open",
       "merge_commit_sha": null,
       "protection_evidence": "not_recorded"
@@ -154,7 +154,7 @@
       "pr": 4285,
       "branch": "feat/4268-ground-contract",
       "base_branch": "feat/4197-capability-observer",
-      "head_sha": "584e4e53a7990053a346938c4e45538786887ec7",
+      "head_sha": "6a2bc9d06f6f9a28a0d615b19d2ed4fc13871059",
       "state": "open",
       "merge_commit_sha": null,
       "protection_evidence": "not_recorded"
@@ -164,7 +164,7 @@
       "pr": 4288,
       "branch": "feat/4269-flight-ground-transfer",
       "base_branch": "feat/4268-ground-contract",
-      "head_sha": "c39297d37a17d5d8d3520ed62c5563cdcc609cab",
+      "head_sha": "4972e55e0bb6e5b6bf7da0f899eed5d4f54e7d9d",
       "state": "open",
       "merge_commit_sha": null,
       "protection_evidence": "not_recorded"
@@ -194,7 +194,7 @@
       "pr": 4302,
       "branch": "feat/4270-ground-impact-bounce",
       "base_branch": "feat/4269-flight-ground-transfer",
-      "head_sha": "62beb3e1aa951645fd556a53f9cbae4bb46c47e5",
+      "head_sha": "cf6e72bad98e5f36f782254942e6895b8b71e670",
       "state": "open",
       "merge_commit_sha": null,
       "protection_evidence": "not_recorded"
@@ -204,7 +204,7 @@
       "pr": 4304,
       "branch": "feat/4271-ground-skid-roll",
       "base_branch": "feat/4270-ground-impact-bounce",
-      "head_sha": "3f861c1faaa7455faee92eaa7f813174667208e0",
+      "head_sha": "0ea6740965068542e9d8c7449e06ec07d88969e0",
       "state": "open",
       "merge_commit_sha": null,
       "protection_evidence": "not_recorded"
@@ -214,7 +214,7 @@
       "pr": 4332,
       "branch": "feat/4271-regional-surface-transitions",
       "base_branch": "feat/4271-ground-skid-roll",
-      "head_sha": "5ac3c1f233de30dd42eeac57073cbdb149bde652",
+      "head_sha": "04ccf08dd990de1cd056a3420e67772773a4be2e",
       "state": "open",
       "merge_commit_sha": null,
       "protection_evidence": "not_recorded"
@@ -224,7 +224,7 @@
       "pr": 4335,
       "branch": "feat/4271-regional-wire-contract",
       "base_branch": "feat/4271-regional-surface-transitions",
-      "head_sha": "8f933ed8dcb29e55ece4ec6bb1e60813f6794d57",
+      "head_sha": "9e01ccc3e891cc45907293751a192624195a77a5",
       "state": "open",
       "merge_commit_sha": null,
       "protection_evidence": "not_recorded"
@@ -234,7 +234,17 @@
       "pr": 4339,
       "branch": "feat/4274-regional-surface-ui",
       "base_branch": "feat/4271-regional-wire-contract",
-      "head_sha": "d21741e312b849a63f73cabf351a15d9de80fb94",
+      "head_sha": "db335937afc4b587d235eb705e315f577519c5e6",
+      "state": "open",
+      "merge_commit_sha": null,
+      "protection_evidence": "not_recorded"
+    },
+    {
+      "id": "pr-4342",
+      "pr": 4342,
+      "branch": "feat/4274-regional-plan-io",
+      "base_branch": "feat/4274-regional-surface-ui",
+      "head_sha": "c1f47f2ef68b3db102da5416aaac17a40f675207",
       "state": "open",
       "merge_commit_sha": null,
       "protection_evidence": "not_recorded"
@@ -423,6 +433,42 @@
         "src/rate_of_closure/AGENT_HANDOFF.md",
         "docs/development/RATE_OF_CLOSURE_CAMPAIGN_HANDOFF.md"
       ]
+    },
+    {
+      "id": "ground-regional-ui-helper-local-d217",
+      "kind": "local",
+      "commit_sha": "d21741e312b849a63f73cabf351a15d9de80fb94",
+      "outcome": "passed",
+      "commands": [
+        "python -m pytest tests/rate_of_closure/test_regional_surface_plan.py tests/rate_of_closure/test_gui.py tests/rate_of_closure/test_layout_minsize.py -q",
+        "npm test -- --run",
+        "npm run type-check && npm run lint && npm run build",
+        "uvx --from ruff==0.14.10 ruff check src/rate_of_closure tests/rate_of_closure && uvx --from ruff==0.14.10 ruff format --check src/rate_of_closure tests/rate_of_closure"
+      ],
+      "summary": "The current PR #4339 parent passed focused Python/PyQt and React qualification plus the complete 672-test React suite after replacing its six-parameter number-input helper with a frozen specification and three-parameter helper. This remains local evidence, not protected release evidence.",
+      "source_paths": [
+        "AGENT_HANDOFF.md",
+        "src/rate_of_closure/AGENT_HANDOFF.md",
+        "docs/development/RATE_OF_CLOSURE_CAMPAIGN_HANDOFF.md"
+      ]
+    },
+    {
+      "id": "ground-regional-io-local-8e1c",
+      "kind": "local",
+      "commit_sha": "8e1c7ccd99a7c4886c5fb9ccc7e4d94a6d7e3833",
+      "outcome": "passed",
+      "commands": [
+        "python -m pytest tests/rate_of_closure/test_regional_surface_plan.py tests/rate_of_closure/test_regional_surface_plan_io.py tests/rate_of_closure/test_workspace_files.py -q",
+        "npm test -- --run src/components/RegionalSurfacePlanPanel.test.tsx",
+        "npm run type-check && npm run lint && npm run build",
+        "uvx --from ruff==0.14.10 ruff check src/rate_of_closure tests/rate_of_closure && uvx --from ruff==0.14.10 ruff format --check src/rate_of_closure tests/rate_of_closure"
+      ],
+      "summary": "The published PR #4342 child passed strict native atomic and bounded browser regional request I/O qualification, safe-number parity, bounded UTF-8 import, static analysis, build, and governance gates before parent reconciliation. Fresh protected evidence remains open.",
+      "source_paths": [
+        "AGENT_HANDOFF.md",
+        "src/rate_of_closure/AGENT_HANDOFF.md",
+        "docs/development/RATE_OF_CLOSURE_CAMPAIGN_HANDOFF.md"
+      ]
     }
   ],
   "programs": [
@@ -1204,7 +1250,8 @@
         "pr-4304",
         "pr-4332",
         "pr-4335",
-        "pr-4339"
+        "pr-4339",
+        "pr-4342"
       ],
       "supported_surfaces": {
         "tools.pyqt6": "implemented_unverified",
@@ -1217,14 +1264,16 @@
         "ground-skid-roll-local-f475",
         "ground-regional-local-1a48",
         "ground-regional-wire-local-74a0",
-        "ground-regional-ui-local-cbb9"
+        "ground-regional-ui-local-cbb9",
+        "ground-regional-ui-helper-local-d217",
+        "ground-regional-io-local-8e1c"
       ],
-      "evidence_gap": "The contract, flight-transfer, impact/bounce, static-plane skid/roll, regional-surface, regional-plan wire, and regional-editor carriers remain open on draft PRs 4285, 4288, 4302, 4304, 4332, 4335, and 4339. Exact local evidence exists, but fresh protected evidence for the reconciled heads, execution/playback, result interchange, workspace model-input persistence, changing geometry, compiled-runtime physics, and downstream parity remain absent.",
+      "evidence_gap": "The contract, flight-transfer, impact/bounce, static-plane skid/roll, regional-surface, regional-plan wire, regional-editor, and regional request-I/O carriers remain open on draft PRs 4285, 4288, 4302, 4304, 4332, 4335, 4339, and 4342. Exact local evidence exists, but fresh protected evidence for the reconciled heads, execution/playback, result interchange, workspace model-input persistence, measured calibration, changing geometry, compiled-runtime physics, and downstream parity remain absent.",
       "limitations": [
         "Airborne flight must first terminate against physical terrain and preserve terminal angular velocity.",
         "Current UpstreamDrift terrain and putting implementations are reference inputs rather than the qualified authority.",
         "The #4270 rigid impact law does not consume firmness, grass, compressibility, moisture, or rolling-resistance fields.",
-        "Published open PR #4304 qualifies one immutable planar profile and optional finite tangent-axis edge; open PR #4332 adds bounded coplanar material overlays; open PR #4335 adds a strict Python/TypeScript plan wire boundary and Python resolver; and open PR #4339 adds matched session-only PyQt6/React request editors. Changing normals, height or velocity discontinuities, terrain deformation, torsional-spin damping, roll-to-skid transitions, internal transition-ledger export, execution/playback, result interchange, measured calibration, workspace model-input persistence, compiled or TypeScript regional physics, and downstream adapters remain unimplemented."
+        "Published open PR #4304 qualifies one immutable planar profile and optional finite tangent-axis edge; open PR #4332 adds bounded coplanar material overlays; open PR #4335 adds a strict Python/TypeScript plan wire boundary and Python resolver; open PR #4339 adds matched PyQt6/React request editors; and open PR #4342 adds editor-qualified canonical request import/export with native atomic semantics and explicit browser limitations. Changing normals, height or velocity discontinuities, terrain deformation, torsional-spin damping, roll-to-skid transitions, internal transition-ledger export, execution/playback, result interchange, measured calibration, workspace model-input persistence, compiled or TypeScript regional physics, and downstream adapters remain unimplemented."
       ],
       "depends_on_issues": [
         4191

docs/specs/GROUND_SKID_ROLL.md

@@ -203,11 +203,23 @@ schema, unit, provenance, and request readback.
 
 The regional v1 wire schema has no calibration record, so the editor does not
 invent one or widen that schema. `unvalidated` is explicit presentation/source
-qualification and is included in the source digest. This first slice is
-session-only: current web workspace file commands do not persist model inputs,
-and neither client claims request export/import, execution, result playback,
-or measured-course calibration. Those capabilities require separate contracts
-and acceptance evidence.
+qualification and is included in the source digest. PyQt6 native Open/Save As
+and React browser import/download persist only the canonical regional request;
+workspace model-input persistence remains a separate contract. Import is
+transactional and accepts only the editor producer/provider v1, fixed qualified
+axis/geometry, and editor row capacity. An unchanged import retains the exact
+request and provenance; editing rebinds the draft digest. Browser downloads
+cannot promise a native path, atomic replacement, or recent-file access.
+Wire numbers are bounded to the shared cross-runtime safe range. Native
+precedence entry preserves every nonnegative integer through
+9,007,199,254,740,991 exactly, so a qualified import cannot be silently narrowed
+before validation or Save As.
+Native import reads one binary handle with a one-byte overflow sentinel before
+strict UTF-8 decoding, so mutable files cannot bypass the 1 MiB allocation cap
+between a metadata check and content parsing.
+Neither client claims execution, result playback, or measured-course
+calibration. Those capabilities require separate contracts and acceptance
+evidence.
 
 Skid and roll distances are accumulated separately from centre speed relative
 to the moving surface. Collinear constant-acceleration segments use the exact