T-11: Validate repository Protocol structural compatibility — minimal approach (Option B)

Problem: Repository modules use structural typing to satisfy Protocol interfaces via
cast(). A function rename, parameter change, or signature mismatch would silently pass
mypy but fail at runtime.

Solution (Option B — minimal):
1. Aligned Protocol signatures in protocols.py with actual implementations:
   - BlocklistRepository: dict[str, object] → dict[str, Any] (matches implementation)
   - ImportLogRepository: dict[str, object] → ImportLogRow (typed model)
   - GeoCacheRepository: dict[str, object] → GeoCacheRow; Iterable → Sequence
   - HistoryArchiveRepository: dict[str, object] → dict[str, Any]
   - ImportLogRepository: async compute_total_pages → sync (matches implementation)

2. Created CI validation script (backend/scripts/validate_repository_protocols.py)
   that runs at build time to ensure all repository modules satisfy their Protocol
   interfaces. Exit 0 if valid, 1 if any mismatch. Detects:
   - Missing functions
   - Parameter count mismatches
   - Type annotation mismatches
   - Return type mismatches

3. Updated backend/app/dependencies.py with explicit docstrings linking each
   get_*_repo() provider to Backend-Development.md § 13.7.1, explaining the
   module-as-Protocol pattern and that it is intentional and validated.

4. Documented the pattern in Backend-Development.md § 13.7.1:
   'Repository Module Pattern — Module-as-Protocol Structural Compatibility'
   explaining why the pattern works, risks (silent breakage), and how the
   validation mitigates it.

5. Fixed type annotation in history_archive_repo.py:
   - get_all_archived_history returns list[dict] → list[dict[str, Any]]
   - Imported Any type

Benefits:
- Prevents silent breakage of repository interfaces
- Formalizes the module-as-Protocol pattern as intentional
- CI validation prevents regressions without refactoring cost
- All repository tests pass (53/53)
- mypy --strict passes on modified files

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Docs/Refactoring.md

@@ -17,4 +17,5 @@ This document catalogues architecture violations, code smells, and structural is
 - Added global domain exception handlers to `backend/app/main.py` so domain exceptions like `JailNotFoundError`, `ConfigValidationError`, and `ConfigWriteError` map consistently to 404, 400, and 500 responses.
 - Fixed stale activation tracking in `backend/app/routers/jail_config.py` by recording `last_activation` only after a successful jail activation and preventing a failed activation attempt from leaving a stale runtime state record.
 - Fixed infinite re-fetch loop in `frontend/src/hooks/useJailConfigs.ts` by wrapping the `onSuccess` callback in `useCallback` with empty dependencies. The bug occurred because `useListData` includes `onSuccess` in its internal `refresh` function's dependency array; an inline callback created a new reference on each render, causing `refresh` to be recreated, which triggered the `useEffect` again, leading to an unbounded fetch loop. Callers of `useListData` must always wrap `onSuccess` callbacks in `useCallback` to maintain reference stability.
+- **T-11 — Repository module-as-Protocol structural type-safety:** Resolved the fragile `cast()` pattern where repository modules were loosely typed against Protocol interfaces. Created a **validation script** (`backend/scripts/validate_repository_protocols.py`) that runs at CI time to ensure all repository modules satisfy their Protocol interfaces. Fixed signature mismatches in `protocols.py` to match actual implementations in `session_repo`, `settings_repo`, `blocklist_repo`, `import_log_repo`, `geo_cache_repo`, `history_archive_repo`, and `fail2ban_db_repo` (correcting return types like `dict[str, Any]` vs `dict[str, object]`, `Sequence` vs `Iterable`, and typed models). Updated `backend/app/dependencies.py` with explicit documentation linking each repository provider to the pattern explained in Backend-Development.md § 13.7.1. **Option B (minimal):** Instead of refactoring to class-based repositories (Option A), the pattern is now formally documented and validated, preventing silent breakage.