feat(pair-corpus-honesty): score non-vendored pointer pairs through a local cache

Task 8.3 (Req 10.1-10.5).

- pairs.py: catalog rows with vendored = false carry their harvest recipe
  and no excerpts; evaluate_catalog harvests them into
  OPENULTRASAST_PAIR_CACHE (default ~/.cache/openultrasast/pairs) only
  when `pairs --pointers` or OPENULTRASAST_PAIRS_NETWORK=1 allows the
  network, otherwise records pointer_pair_skipped (a failed fetch is
  pointer_pair_fetch_failed with detail); a warm cache never scores
  without the switch. select_vendored for tests and gates.
- harvest.py: materialize_pointer harvests into the cache without the
  license requirement (nothing is redistributed); redaction applies.
- catalog_gen.py: emits pointer rows with recipe fields; training
  manifests skip them.
- pair_gate and improve/evolve.evaluate_profiles score vendored pairs
  only; cli `pairs --pointers`; .gitignore covers the cache path.
- tests: loader, skip/degradation, cache hit, fetch failure, warm cache
  with network off, profile gate exclusion, harvest and generator paths;
  conftest keeps every test offline whatever the shell exports.

Co-Authored-By: Claude Fable 5.1 <[email protected]>
Claude-Session: https://claude.ai/code/session_01T7XD7x5KonMdmGRkp63EQG

.gitignore

@@ -19,6 +19,8 @@ build/
 *.egg-info/
 
 **/.openultrasast/
+.cache/openultrasast/
+**/.cache/openultrasast/
 artifacts/
 reports/
 vector-store/