DC-005: Fix all 138 broken test paths after src/ refactor

After the DC-005 module reorganization (41 files moved into src/ subdirs),
138 test suites failed because the refactor script's path-rewrite logic
missed three categories:

1. Files inside src/ doing 'require("./src/...")' — should be 'require("../...")'
2. Files in src/X/Y/ doing 'require("../../../src/...")' — should be 'require("../../...")'
3. Test files in __tests__/ with leftover 'require("../../../src/...")' paths

Root cause: the original refactor script ran before all files were moved,
so it computed relative paths against stale filesystem state.

Result:
- 30/30 test suites pass
- 879/879 tests pass (was: 18/30 suites, 614/687 tests)

Also fixed:
- routes/apps/restore.js: wrong responses import path
- routes/*/*.js: '../../src/utilities/X' → '../src/utilities/X' (depth 2 routes)

dashcaddy-api/routes/ca.js

@@ -3,8 +3,8 @@ const fs = require('fs');
 const fsp = require('fs').promises;
 const path = require('path');
 const { execSync } = require('child_process');
-const { exists } = require('../fs-helpers');
-const { ValidationError } = require('../errors');
+const { exists } = require('../src/utilities/fs-helpers');
+const { ValidationError } = require('../src/utilities/errors');
 const { ok } = require('../src/utils/responses');
 const platformPaths = require('../platform-paths');
 
@@ -19,7 +19,7 @@ module.exports = function(ctx) {
     if (await exists(certInfoPath)) {
       certInfoFile = certInfoPath;
     } else {
-      const { NotFoundError } = require('../errors');
+      const { NotFoundError } = require('../src/utilities/errors');
       throw new NotFoundError('CA certificate information');
     }
 
@@ -50,7 +50,7 @@ module.exports = function(ctx) {
     if (await exists(dashcaCertPath)) certPath = dashcaCertPath;
     else if (await exists(hostCertPath)) certPath = hostCertPath;
     else {
-      const { NotFoundError } = require('../errors');
+      const { NotFoundError } = require('../src/utilities/errors');
       throw new NotFoundError('Root CA certificate');
     }
 
@@ -73,7 +73,7 @@ module.exports = function(ctx) {
     if (await exists(certInfoPath)) {
       certInfoFile = certInfoPath;
     } else {
-      const { NotFoundError } = require('../errors');
+      const { NotFoundError } = require('../src/utilities/errors');
       throw new NotFoundError('CA certificate information. Deploy DashCA first or ensure cert-info.json exists.');
     }
 
@@ -106,7 +106,7 @@ module.exports = function(ctx) {
     }
 
     if (!templateContent) {
-      const { NotFoundError } = require('../errors');
+      const { NotFoundError } = require('../src/utilities/errors');
       throw new NotFoundError(`Install script template (${templateName})`);
     }