REUSE-WP-0018 T01/T02/T04/T06: plan-check deterministic matching + State Hub bridge

T01: specs/PlanCheck.md design doc, plan-check-result.schema.json and
reuse-event.schema.json (the latter shared with WP-0019's reuse telemetry).

T02: reuse_surface/plan_check.py + 'reuse-surface plan-check' CLI command.
Deterministic token-Jaccard matching against registry/indexes/federated.yaml
(reuses overlaps.py's TOKEN_RE rather than a second scoring method), with
reuse/extend/new verdicts, markdown and --format json output, staleness
warning, and --record-outcome JSONL telemetry.

T04: reuse_surface/statehub_bridge.py bridges plan-check 'new' verdicts to
State Hub capability requests (--file-request) and surfaces open requests
with no matching capability (report gaps --check-capability-requests, opt-in
to stay offline-safe). Verified against the live local State Hub API;
status field (not catalog_entry_id presence) is the correct open/closed
signal, and the list endpoint needs a longer timeout than the health check
(~7s observed with 5 rows).

T06: docs (tools/README.md, RegistryFederation.md, SCOPE.md,
IntentScopeGapAnalysis.md priority 29) and an informational CI smoke step.

T03 (LLM rerank) not started -- llm-connect isn't running on this
workstation. T05 (ecosystem rollout) remains blocked: WP-0017 has drafted
entries for all 61 repos but they're still local-only pending its own T05
push/publish pass, so the federated index isn't yet worth rolling out
plan-check as ecosystem convention.

16 new tests, all mocked -- no network calls in the default test run.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

tests/test_reports.py

@@ -158,6 +158,29 @@ def test_cmd_report_gaps_json(monkeypatch):
     assert exit_code == 0
 
 
+def test_cmd_report_gaps_check_capability_requests_unreachable(monkeypatch):
+    from reuse_surface.cli import main
+
+    monkeypatch.setattr(
+        "reuse_surface.cli.list_open_capability_requests", lambda: None
+    )
+    exit_code = main(["report", "gaps", "--check-capability-requests"])
+    assert exit_code == 0
+
+
+def test_cmd_report_gaps_check_capability_requests_json(monkeypatch):
+    from reuse_surface.cli import main
+
+    monkeypatch.setattr(
+        "reuse_surface.cli.list_open_capability_requests",
+        lambda: [{"id": "r1", "title": "Need X", "requesting_domain_slug": "infotech"}],
+    )
+    exit_code = main(
+        ["report", "gaps", "--check-capability-requests", "--format", "json"]
+    )
+    assert exit_code == 0
+
+
 def test_cmd_report_cohorts_markdown(monkeypatch):
     from reuse_surface.cli import main