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/routers/config_misc.py

@@ -5,13 +5,14 @@ from pathlib import Path
 from typing import Annotated
 
 import structlog
-from fastapi import APIRouter, Query, Request, status
+from fastapi import APIRouter, Depends, Query, Request, status
 
 from app.config import get_settings
 from app.dependencies import (
     AuthDep,
     Fail2BanSocketDep,
     Fail2BanStartCommandDep,
+    GlobalRateLimiterDep,
     SettingsServiceContextDep,
 )
 from app.exceptions import OperationError
@@ -33,11 +34,46 @@ from app.services import (
     jail_service,
     log_service,
 )
+from app.utils.constants import RATE_LIMIT_CONFIG_UPDATE_REQUESTS
 
 log: structlog.stdlib.BoundLogger = structlog.get_logger()
 
 router: APIRouter = APIRouter(tags=["Config Misc"])
 
+# Rate limit bucket constants
+_CONFIG_UPDATE_BUCKET = "config:update"
+# 60 seconds per minute
+_MINUTE = 60
+
+
+def _check_config_update_rate_limit(
+    request: Request,
+    rate_limiter: GlobalRateLimiterDep,
+) -> None:
+    """Check rate limit for config update operations."""
+    from app.utils.client_ip import get_client_ip
+
+    settings = request.app.state.settings
+    client_ip = get_client_ip(request, trusted_proxies=settings.trusted_proxies)
+    is_allowed, retry_after = rate_limiter.check_allowed_for_bucket(
+        _CONFIG_UPDATE_BUCKET, client_ip, RATE_LIMIT_CONFIG_UPDATE_REQUESTS, _MINUTE
+    )
+    if not is_allowed:
+        from app.exceptions import RateLimitError
+        import structlog
+
+        log = structlog.get_logger()
+        log.warning(
+            "config_update_rate_limit_exceeded",
+            client_ip=client_ip,
+            path=request.url.path,
+            retry_after=retry_after,
+        )
+        raise RateLimitError(
+            "Rate limit exceeded for config updates. Please try again later.",
+            retry_after_seconds=retry_after,
+        )
+
 
 def _validate_log_target(value: str) -> None:
     """Validate that log_target is either a special value or a valid file path.
@@ -103,6 +139,7 @@ async def get_global_config(
     "/global",
     status_code=status.HTTP_204_NO_CONTENT,
     summary="Update global fail2ban settings",
+    dependencies=[Depends(_check_config_update_rate_limit)],
 )
 async def update_global_config(
     _request: Request,
@@ -296,6 +333,7 @@ async def get_map_color_thresholds(
     "/map-color-thresholds",
     response_model=MapColorThresholdsResponse,
     summary="Update map color threshold configuration",
+    dependencies=[Depends(_check_config_update_rate_limit)],
 )
 async def update_map_color_thresholds(
     _request: Request,