Sixth per-module ratchet under ADR 0004. Cover the queue/audit
malformed-input and fallback branches:
- path helpers (bot_bottle_root, queue_dir_for_slug,
_id_from_proposal_filename non-match)
- read_proposal / read_response reject non-object JSON
- list_pending_proposals skips unreadable/non-dict/incomplete
proposals and ones with a response already present
- wait_for_response tolerates a malformed or incomplete response file
and then times out at the deadline
- read_audit_entries returns [] for a missing log and skips blank /
non-JSON / non-dict / missing-field lines
- the fcntl flock helpers swallow OSError on a bad fd
supervise.py: 89% -> 99%. The one remaining line is an unreachable
`continue` (glob already guarantees the .proposal.json suffix).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NkwFXLFff9PYPy4wgVBJp9
