Bounded recovery loop for hard verification failures

[mmprotest]

Motivation

• Prevent runtime/syntax crashes from counting as verification success and stop delete-and-regenerate recovery that lost failing-file context.
• Add a minimal, generic bounded recovery mode that forces a read→fix→rerun loop on the exact failing file and returns compact structured feedback when blocking disallowed actions.

Description

• Added a compact recovery state on the runner (_recovery_mode, _failing_file, _failing_error_summary, _failing_command, _file_was_read_since_failure) and initialize/reset it at run start in Runner (villani_code/state.py).
• Detect hard verification failures inside run_verification in villani_code/state_runtime.py via _detect_hard_failure(...) and when found: force VerificationStatus.FAIL, reduce confidence, capture failing_file/error_summary/failing_command, and activate recovery_mode; clear recovery only after a successful verification pass or repaired state.
• Enforce bounded recovery behavior by extending small_model_tool_guard(...) in villani_code/state_runtime.py to: block edits that are not targeted at the active failing file, block edits to the failing file until it has been read since the failure, block delete/regenerate (patch delete or empty Write) and large rewrites of the failing file, and return compact JSON feedback via _recovery_blocked_feedback(...).
• Apply the guard unconditionally in execute_tool_with_policy(...) (villani_code/state_tooling.py) so recovery checks run regardless of small-model/benchmark flags, and mark the failing-file read flag (_file_was_read_since_failure) on successful Read tool results in both state_tooling.execute_tool_with_lifecycle and the runner tool loop (villani_code/state.py).
• Small, surgical changes only; reused existing verification/mission/session structures and existing tool lifecycle to avoid large refactors.
• Files changed: villani_code/state_runtime.py (hard-failure detection, helpers, guard extension), villani_code/state.py (runner fields, tool-loop read/flag handling, reset), villani_code/state_tooling.py (apply guard earlier, mark read), and tests updated/added in tests/test_state_runtime.py and tests/test_state_tooling_mutation_policy.py.

Testing

• Added unit tests: test_syntax_error_does_not_mark_verification_pass, test_name_error_does_not_mark_verification_pass, test_hard_failure_sets_recovery_mode_state, test_successful_rerun_clears_recovery_mode, test_recovery_mode_blocks_delete_of_active_failing_file, test_recovery_mode_blocks_edit_without_read_first, and test_read_failing_file_flips_recovery_read_flag in the two modified test files.
• Ran: pytest -q tests/test_state_runtime.py tests/test_state_tooling_mutation_policy.py and observed all tests passing: 47 passed.

---

Codex Task