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/recipes/index.js

@@ -1,6 +1,7 @@
 const express = require('express');
 const deployRoutes = require('./deploy');
 const manageRoutes = require('./manage');
+const { NotFoundError } = require('../../errors');
 
 module.exports = function(ctx) {
   const router = express.Router();
@@ -41,7 +42,7 @@ module.exports = function(ctx) {
   router.get('/templates/:recipeId', ctx.asyncHandler(async (req, res) => {
     const { RECIPE_TEMPLATES } = require('../../recipe-templates');
     const recipe = RECIPE_TEMPLATES[req.params.recipeId];
-    if (!recipe) return ctx.errorResponse(res, 404, 'Recipe template not found');
+    if (!recipe) throw new NotFoundError(`Recipe template ${req.params.recipeId}`);
 
     res.json({ success: true, recipe: { id: req.params.recipeId, ...recipe } });
   }, 'recipe-template-detail'));