feat(1259-01): deterministic prohibition-enforcement producer + check route

- Author src/prohibition-enforcement.cts: the test-tier prohibition PRODUCER/gate (ADR-550 D5d heavy half)
  locate wired check (node-test|lint-rule) -> confirm fail-first -> run -> build enforcementEvidence -> dispositionForProhibition
  pure/deterministic with injectable runCheck; missing/failing/non-fail-first -> hard-gate (both modes); passing -> green
- Route check prohibition-enforcement in src/check-command-router.cts (same family as ui-plan-gate / tdd-review-checkpoint)
- Add tests/prohibition-enforcement.test.cjs (behavioral, typed-field, injected runner) — new module within <=2 budget
- Register the built bin/lib surface: docs/INVENTORY.md row + regenerated docs/INVENTORY-MANIFEST.json
- .gitignore: add the emitted gsd-core/bin/lib/prohibition-enforcement.cjs (build artifact, ADR-457)
- No src/probe-core.cts edit — the green/fail-closed policy seam already exists

docs/INVENTORY-MANIFEST.json

@@ -344,6 +344,7 @@
       "profile-output.cjs",
       "profile-pipeline-command-router.cjs",
       "profile-pipeline.cjs",
+      "prohibition-enforcement.cjs",
       "project-root.cjs",
       "prompt-budget.cjs",
       "research-provider.cjs",

docs/INVENTORY.md

@@ -459,6 +459,7 @@ Full listing: `gsd-core/bin/lib/*.cjs`.
 | `research-provider.cjs` | Research provider waterfall, confidence tiers, and planResearch (cache-hits + fetch plan) |
 | `research-store.cjs` | Content-addressed research cache: sha256 keys, per-source TTL staleness, two-tier (user ~/.gsd / project .planning) store |
 | `probe-core.cjs` | Generic spec-phase probe resolution model (compiled from `src/probe-core.cts`, gitignored; ADR-550 Decision 7) — the status×verification re-cut (`status: resolved/dismissed/unresolved` × per-probe `verification`), `validateResolution`/`validateRequirement`, `analyzeCoverage(items, resolutions?, validators)` merge/rollup/orphan-reject, the `byVerification` rollup, and the `runProbeCli` I/O scaffold; the shared seam consumed by `edge-probe` (and the prohibition probe #644); exports `VALID_STATUS`, `validateResolution`, `validateRequirement`, `analyzeCoverage`, `runProbeCli` (#550) |
+| `prohibition-enforcement.cjs` | Deterministic test-tier prohibition PRODUCER/gate (compiled from `src/prohibition-enforcement.cts`, gitignored; #1259, ADR-550 D5d "heavy half") — locates the wired mechanical check (`node-test` or `lint-rule`), confirms it is fail-first, runs it via an injectable runner, builds typed `enforcementEvidence`, and emits the `dispositionForProhibition` verdict; a passing wired check disposes green, a missing/failing/non-fail-first check hard-gates (flagged, non-green) in both interactive and autonomous modes; exports `runProhibitionEnforcement`, `routeProhibitionEnforcement`; CLI surface `gsd_run check prohibition-enforcement <request.json>` |
 | `review-reviewer-selection.cjs` | Reviewer selection/normalization helpers for `/gsd-review` default reviewer policy and precedence |
 | `roadmap-command-router.cjs` | Thin CJS subcommand router adapter for `gsd-tools roadmap` |
 | `roadmap-parser.cjs` | ROADMAP.md parsing — milestone slicing, current-milestone extraction, phase/milestone lookups, milestone-phase filter (extracted from `core.cjs`, ADR-857) |