feat: implement API versioning /api/v1/

- All backend routers moved to /api/v1/ prefix
- Frontend BASE_URL updated to /api/v1
- Setup redirect middleware updated to redirect to /api/v1/setup
- Health router path fixed: prefix=/api/v1/health, @router.get('')
- conftest.py: set server_status=online for test fixture
- Created Docs/API_VERSIONING.md with deprecation policy
- Updated Docs/Backend-Development.md with versioning section
- Updated Instructions.md curl examples

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

backend/app/repositories/protocols.py

@@ -301,6 +301,37 @@ class HistoryArchiveRepository(Protocol):
     async def purge_archived_history(self, db: aiosqlite.Connection, age_seconds: int) -> int:
         ...
 
+    async def get_ip_ban_counts(
+        self,
+        db: aiosqlite.Connection,
+        since: int | None = None,
+        jail: str | None = None,
+        ip_filter: str | list[str] | None = None,
+        origin: BanOrigin | None = None,
+        action: str | None = None,
+    ) -> list[dict[str, Any]]:
+        ...
+
+    async def get_jail_ban_counts(
+        self,
+        db: aiosqlite.Connection,
+        since: int | None = None,
+        origin: BanOrigin | None = None,
+        action: str | None = None,
+    ) -> tuple[int, list[dict[str, Any]]]:
+        ...
+
+    async def get_ban_counts_by_bucket(
+        self,
+        db: aiosqlite.Connection,
+        since: int,
+        bucket_secs: int,
+        num_buckets: int,
+        origin: BanOrigin | None = None,
+        action: str | None = None,
+    ) -> list[int]:
+        ...
+
 
 class Fail2BanDbRepository(Protocol):
     async def check_db_nonempty(self, db_path: str) -> bool: