[grade=A] DC-068: Fix all 3 ESLint errors + auto-fix warnings

- Removed orphaned __trace2.js (unnecessary escape error)
- Fixed empty block statement in config-migrations.test.js busy-wait
- Fixed empty block statement in metrics.test.js busy-wait
- Auto-fixed 5 fixable warnings via eslint --fix
- Remaining 547 warnings (require-await, no-unused-vars) are non-blocking code quality
- 0 errors, 1633 tests pass

dashcaddy-api/__tests__/update-manager.test.js

@@ -778,11 +778,11 @@ describe('UpdateManager — Docker image update lifecycle', () => {
           statusCode: 200,
           headers: {},
           on: jest.fn((event, handler) => {
-            if (event === 'data') handler(Buffer.from(JSON.stringify({
+            if (event === 'data') {handler(Buffer.from(JSON.stringify({
               description: 'Plex Media Server',
               pull_count: 1000000,
               star_count: 500
-            })));
+            })));}
             if (event === 'end') handler();
           })
         }));
@@ -830,12 +830,12 @@ describe('UpdateManager — Docker image update lifecycle', () => {
           statusCode: 200,
           headers: {},
           on: jest.fn((event, handler) => {
-            if (event === 'data') handler(Buffer.from(JSON.stringify({
+            if (event === 'data') {handler(Buffer.from(JSON.stringify({
               results: [
                 { name: 'latest', last_pushed: '2026-04-01T00:00:00Z' },
                 { name: '1.40', last_pushed: '2026-03-15T00:00:00Z' }
               ]
-            })));
+            })));}
             if (event === 'end') handler();
           })
         }));