refactor(harnessx-removal): retire the HarnessX scan paths (task 5)

The standard scan now runs run_hunter_pool, verify_findings and the
deterministic fuse_findings directly; the HarnessX hunter orchestrator,
the LLM judge dispatcher (verify_judge.py, deleted with its test) and the
LLM fusion panels are gone, and so are their extra-absent degradations.
host_under_harnessx is dropped from stage_processors.

config: [models] verifier and [fusion] panel_model/decider_model raise
RetiredConfigError naming the plane replacement (the CLI prints it and
exits 2); a [harnessx] section loads with one warning and is otherwise
ignored. harness.json keeps "verifier": null. Tests that asserted the
fallback are renamed to the behaviour they assert; the module-audit
manifest drops verify_judge. Nothing outside the two modules deleted in
task 6 imports harness_ext or hunter_harness.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01EmM1j46qgKMh3zqD1QMwEo

.kiro/specs/harnessx-removal/tasks.md

@@ -38,7 +38,7 @@ and passed its fixture test. Every task is a commit gated on the full suite's ow
     passes it reuses from memory).
   - _Requirements: 6.3_
 
-- [ ] 5. Retire the HarnessX scan paths
+- [x] 5. Retire the HarnessX scan paths
   - `cli.py`, `fusion.py`, `verify_judge.py`, `stage_processors.py` changes; `RetiredConfigError` for
     `[models] verifier`, `[fusion] panel_model`/`decider_model`; one warning for a `[harnessx]` section (the only
     tagged retirement text allowed in `src`, enforced by a test); tests renamed to the behaviour they assert.