Migrate 25 route files to throw-based error handling

Converted routes:
- All auth routes (totp.js, keys.js, sso-gate.js)
- Recipe deployment routes (deploy.js, manage.js, index.js)
- App deployment routes
- Config routes (assets, backup, settings)
- ARR routes (config, credentials)
- Infrastructure routes (dns, services, sites, logs)
- Additional routes (browse, ca, health, license, notifications, tailscale, updates)

Changes:
- Replaced ctx.errorResponse() with throw statements
- Replaced errorResponse() with throw statements
- Added proper error imports to each file
- 400 errors → ValidationError
- 401 errors → AuthenticationError
- 403 errors → ForbiddenError
- 404 errors → NotFoundError
- 409 errors → ConflictError
- 500 errors → Handled by middleware

Result: 25 files migrated, ~150 error responses standardized

dashcaddy-api/routes/updates.js

@@ -1,5 +1,6 @@
 const express = require('express');
 const { paginate, parsePaginationParams } = require('../pagination');
+const { ValidationError } = require('../errors');
 
 module.exports = function(ctx) {
   const router = express.Router();
@@ -53,7 +54,7 @@ module.exports = function(ctx) {
   router.post('/updates/schedule/:containerId', ctx.asyncHandler(async (req, res) => {
     const { scheduledTime } = req.body;
     if (!scheduledTime) {
-      return ctx.errorResponse(res, 400, 'scheduledTime is required');
+      throw new ValidationError('scheduledTime is required');
     }
     ctx.updateManager.scheduleUpdate(req.params.containerId, scheduledTime);
     res.json({ success: true, message: 'Update scheduled', scheduledTime });
@@ -116,7 +117,7 @@ module.exports = function(ctx) {
   // Rollback to a previous version
   router.post('/system/rollback', ctx.asyncHandler(async (req, res) => {
     const { version } = req.body;
-    if (!version) return ctx.errorResponse(res, 400, 'version is required');
+    if (!version) throw new ValidationError('version is required');
     ctx.selfUpdater.rollbackToVersion(version).catch(err => {
       ctx.logError('self-rollback', err);
     });