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>

frontend/translations/en.json

@@ -1184,6 +1184,7 @@
   "nav.skip_to_content": "Skip to main content",
   "nav.status": "Status",
   "nav.subscription": "Subscription",
+  "nav.system_reset": "System Reset",
   "nav.toggle_dark_mode": "Toggle dark mode",
   "nav.toggle_nav": "Toggle navigation menu",
   "nav.upload": "Upload",
@@ -1723,6 +1724,36 @@
   "subscription.upgrade_info": "Upgrades take effect immediately. Downgrades are scheduled for the end of your current billing period.",
   "subscription.upgrade_to_prefix": "Upgrade to",
   "subscription.usage_heading": "Usage",
+  "system_reset.danger_desc": "The actions below will permanently destroy data. They cannot be undone. Application settings and configuration are preserved, but all documents, files, processing history, and audit logs will be deleted.",
+  "system_reset.danger_zone": "Danger Zone — Irreversible Actions",
+  "system_reset.full_reset_button": "Wipe All Data",
+  "system_reset.full_reset_desc": "Permanently deletes all user data from the database and removes all work files from disk. The application will be in its initial state after this operation.",
+  "system_reset.full_reset_item_cache": "All watch-folder caches and ingestion state",
+  "system_reset.full_reset_item_db": "All document records, processing logs, and audit history",
+  "system_reset.full_reset_item_files": "All original, processed, and temporary files on disk",
+  "system_reset.full_reset_item_settings_kept": "Application settings and configuration are preserved",
+  "system_reset.full_reset_subtitle": "Wipe everything and start fresh",
+  "system_reset.full_reset_title": "Full System Reset",
+  "system_reset.heading": "System Reset",
+  "system_reset.js_error_generic": "An error occurred. Please check the server logs for details.",
+  "system_reset.js_success_full": "System reset complete. All user data has been wiped.",
+  "system_reset.js_success_reimport": "Reset complete. Original files have been staged for re-import via the watch folder.",
+  "system_reset.page_title": "System Reset",
+  "system_reset.reimport_button": "Reset & Re-import",
+  "system_reset.reimport_desc": "Copies your original files to a special reimport folder, wipes everything, then lets the watch-folder mechanism re-process them as if they were freshly uploaded.",
+  "system_reset.reimport_note": "Re-imported files will go through the full processing pipeline with the same rate limits and backoff strategy as regular uploads.",
+  "system_reset.reimport_step_1": "Original files are copied to a dedicated reimport folder",
+  "system_reset.reimport_step_2": "All data (database + work files) is wiped clean",
+  "system_reset.reimport_step_3": "The reimport folder is configured as a watch folder for automatic re-ingestion",
+  "system_reset.reimport_subtitle": "Wipe and re-process all original files",
+  "system_reset.reimport_title": "Reset & Re-import",
+  "system_reset.startup_reset_active": "Factory Reset on Startup is ACTIVE",
+  "system_reset.startup_reset_desc": "FACTORY_RESET_ON_STARTUP is enabled. All user data is wiped every time the application starts.",
+  "system_reset.subtitle": "Reset DocuElevate to a clean, fresh state. All user data will be permanently deleted.",
+  "system_reset.type_delete": "Type DELETE to confirm",
+  "system_reset.type_delete_help": "You must type the word DELETE in capital letters to enable the reset button.",
+  "system_reset.type_reimport": "Type REIMPORT to confirm",
+  "system_reset.type_reimport_help": "You must type the word REIMPORT in capital letters to enable the button.",
   "terms.cookie_link": "Cookie Policy",
   "terms.heading": "Terms of Service",
   "terms.last_updated": "Last Updated:",