feat(system-reset): add system reset and factory reset feature

- Add FACTORY_RESET_ON_STARTUP and ENABLE_FACTORY_RESET config settings
- Create app/utils/system_reset.py with core reset logic (wipe DB + files, reimport)
- Create app/api/system_reset.py with admin-only API endpoints
- Create app/views/system_reset.py with admin-only UI view
- Create frontend/templates/system_reset.html with confirmation dialogs
- Auto-reset on startup when FACTORY_RESET_ON_STARTUP=true
- Re-import uses watch folder mechanism for re-ingestion
- Register routers in API and views init files
- Add i18n keys and SETTING_METADATA entries
- Add nav links in base.html (desktop + mobile)

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

app/views/base.py

@@ -94,6 +94,7 @@ def _inject_global_context(ctx: dict) -> None:
         "allow_signup",
         getattr(settings, "multi_user_enabled", False) and getattr(settings, "allow_local_signup", False),
     )
+    ctx.setdefault("enable_factory_reset", getattr(settings, "enable_factory_reset", False))
 
     req = ctx.get("request")
     if req is not None: