REUSE-WP-0018-T03: LLM semantic rerank for plan-check

llm-connect came up locally (mock provider, 127.0.0.1:8080), unblocking
this task.

reuse_surface/plan_check.py: build_rerank_prompt/request_rerank/apply_rerank,
reusing llm_bridge.execute_prompt/extract_json_object (same pattern as
maintain_llm.py's request_maintain_patches). New schema
schemas/plan-check-rerank.schema.json rejects malformed responses (missing
fields, non-JSON, invented candidate ids outside the input set) rather than
guessing.

Per design principle 3 (deterministic matches always rank first),
apply_rerank appends LLM-scored entries after the deterministic list
(kind: 'llm') instead of reordering it -- the trusted base result is
identical with or without the rerank pass. Graceful skip via a 'notes'
field when LLM_CONNECT_URL is unset or the response is malformed, mirroring
maintain.py's no_llm/skip pattern. New --llm-url/--no-llm CLI flags.

Also extended plan-check-result.schema.json for 'notes' and the
(pre-existing, previously unschema'd) 'filed_capability_request' field.

9 new pytest cases; 89 total pass. Live-verified against the running
llm-connect instance: it correctly rejected the mock provider's non-JSON
response and surfaced the skip note, with the deterministic verdict and
match order completely unaffected.

REUSE-WP-0018 is now fully done (T01-T06). Updated
docs/IntentScopeGapAnalysis.md priority 29 to Closed and the workplan's
own frontmatter status to finished.

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

reuse_surface/cli.py

@@ -608,6 +608,8 @@ def cmd_plan_check(args: argparse.Namespace) -> int:
         query,
         reuse_threshold=args.reuse_threshold,
         extend_threshold=args.extend_threshold,
+        use_llm=not args.no_llm,
+        llm_url=args.llm_url,
     )
 
     if args.record_outcome:
@@ -812,6 +814,13 @@ def main(argv: list[str] | None = None) -> int:
         "--requesting-domain", default="infotech",
         help="domain slug recorded on a filed capability request",
     )
+    plan_check.add_argument(
+        "--llm-url", help="llm-connect base URL (or LLM_CONNECT_URL) for semantic rerank",
+    )
+    plan_check.add_argument(
+        "--no-llm", action="store_true",
+        help="skip the optional LLM semantic rerank pass",
+    )
     plan_check.set_defaults(func=cmd_plan_check)
 
     catalog = subparsers.add_parser(