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/action_config.py

@@ -2,9 +2,9 @@ from __future__ import annotations
 
 from typing import Annotated
 
-from fastapi import APIRouter, Path, Query, Request, status
+from fastapi import APIRouter, Depends, Path, Query, Request, status
 
-from app.dependencies import AuthDep, Fail2BanConfigDirDep, Fail2BanSocketDep
+from app.dependencies import AuthDep, Fail2BanConfigDirDep, Fail2BanSocketDep, GlobalRateLimiterDep
 from app.models.config import (
     ActionConfig,
     ActionCreateRequest,
@@ -12,9 +12,108 @@ from app.models.config import (
     ActionUpdateRequest,
 )
 from app.services import action_config_service
+from app.utils.constants import (
+    RATE_LIMIT_ACTION_CREATE_REQUESTS,
+    RATE_LIMIT_ACTION_DELETE_REQUESTS,
+    RATE_LIMIT_ACTION_UPDATE_REQUESTS,
+)
 
 router: APIRouter = APIRouter(prefix="/actions", tags=["Action Config"])
 
+_MINUTE = 60
+
+_ACTION_UPDATE_BUCKET = "action:update"
+_ACTION_CREATE_BUCKET = "action:create"
+_ACTION_DELETE_BUCKET = "action:delete"
+
+
+def _check_action_update_rate_limit(
+    request: Request,
+    rate_limiter: GlobalRateLimiterDep,
+) -> None:
+    """Check rate limit for action 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(
+        _ACTION_UPDATE_BUCKET, client_ip, RATE_LIMIT_ACTION_UPDATE_REQUESTS, _MINUTE
+    )
+    if not is_allowed:
+        from app.exceptions import RateLimitError
+        import structlog
+
+        log = structlog.get_logger()
+        log.warning(
+            "action_update_rate_limit_exceeded",
+            client_ip=client_ip,
+            path=request.url.path,
+            retry_after=retry_after,
+        )
+        raise RateLimitError(
+            "Rate limit exceeded for action update operations. Please try again later.",
+            retry_after_seconds=retry_after,
+        )
+
+
+def _check_action_create_rate_limit(
+    request: Request,
+    rate_limiter: GlobalRateLimiterDep,
+) -> None:
+    """Check rate limit for action create 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(
+        _ACTION_CREATE_BUCKET, client_ip, RATE_LIMIT_ACTION_CREATE_REQUESTS, _MINUTE
+    )
+    if not is_allowed:
+        from app.exceptions import RateLimitError
+        import structlog
+
+        log = structlog.get_logger()
+        log.warning(
+            "action_create_rate_limit_exceeded",
+            client_ip=client_ip,
+            path=request.url.path,
+            retry_after=retry_after,
+        )
+        raise RateLimitError(
+            "Rate limit exceeded for action create operations. Please try again later.",
+            retry_after_seconds=retry_after,
+        )
+
+
+def _check_action_delete_rate_limit(
+    request: Request,
+    rate_limiter: GlobalRateLimiterDep,
+) -> None:
+    """Check rate limit for action delete 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(
+        _ACTION_DELETE_BUCKET, client_ip, RATE_LIMIT_ACTION_DELETE_REQUESTS, _MINUTE
+    )
+    if not is_allowed:
+        from app.exceptions import RateLimitError
+        import structlog
+
+        log = structlog.get_logger()
+        log.warning(
+            "action_delete_rate_limit_exceeded",
+            client_ip=client_ip,
+            path=request.url.path,
+            retry_after=retry_after,
+        )
+        raise RateLimitError(
+            "Rate limit exceeded for action delete operations. Please try again later.",
+            retry_after_seconds=retry_after,
+        )
+
+
 _ActionNamePath = Annotated[
     str,
     Path(description='Action base name, e.g. ``iptables`` or ``iptables.conf``.'),
@@ -105,6 +204,7 @@ async def get_action(
     "/{name}",
     response_model=ActionConfig,
     summary="Update an action's .local override with new lifecycle command values",
+    dependencies=[Depends(_check_action_update_rate_limit)],
 )
 async def update_action(
     request: Request,
@@ -145,6 +245,7 @@ async def update_action(
     response_model=ActionConfig,
     status_code=status.HTTP_201_CREATED,
     summary="Create a new user-defined action",
+    dependencies=[Depends(_check_action_create_rate_limit)],
 )
 async def create_action(
     request: Request,
@@ -182,6 +283,7 @@ async def create_action(
     "/{name}",
     status_code=status.HTTP_204_NO_CONTENT,
     summary="Delete a user-created action's .local file",
+    dependencies=[Depends(_check_action_delete_rate_limit)],
 )
 async def delete_action(
     request: Request,