Fix 10 audit bugs: path prefix matching, verdict parsing, CORS, stale-task detection, phase mapping

Batch 1 (High severity):
- Bug 1: --audit cat3 now checks .automaton/tasks/ paths
- Bug 4: Verdict PASS/FAIL uses structured ## Status: line parsing
- Bug 5: register-guards.sh checks .json/.jsonc, writes plugin key, strips comments
- Bug 7: --can-edit/--scope-check path prefix uses os.sep boundary

Batch 2 (Medium/Low severity):
- Bug 2: migrate-project.sh find command parentheses for -prune binding
- Bug 3: vram_detect model prefix matching with known-suffix whitelist
- Bug 6: dashboard reads .state file before artifact heuristic fallback
- Bug 8: removed wildcard CORS, added security headers (nosniff, DENY)
- Bug 9: stale-task detection uses .state.lastedit instead of .state mtime
- Bug 10: TEST_PLAN.md maps to test_design (was implement)

249 tests pass (up from 235). All 10 tasks driven through full workflow to completion.

tasks/fix-cat3-audit-paths/ADVERSARIAL_BUG_REPORT.md

@@ -0,0 +1,18 @@
+# Adversarial Bug Report: fix-cat3-audit-paths
+
+## Summary
+Adversarial review of the Category 3 audit path fix. No additional bugs found.
+
+## Bugs Found
+No bugs found.
+
+## Analysis
+- **Race conditions**: `_audit_category3` reads git diff state at a point in time. No concurrent modification risk since it's a read-only audit.
+- **Path traversal**: The check uses `Path(changed_file).parts` which splits on path separators — no traversal bypass possible.
+- **Edge case — nested subtasks**: `.automaton/tasks/parent/subtasks/child/file` has `parts[2]` = `parent`, which is in `task_names` (subtasks are listed as `parent` in `_all_task_dirs`). Correctly excluded.
+- **Edge case — empty task_names**: If `tasks` is empty, `task_names` is empty, and no file matches — all files flagged as unauthorized. This is correct behavior (no tasks = no authorized edits).
+
+## Score
+0
+
+ADVERSARIAL_BUG_FIND_COMPLETE