fix(lint): resolve pre-existing lint errors and merge conflicts

- Remove unused imports/vars from routes.ts (VALID_TRANSITIONS, AUTOMATION_PRESETS, ChatStore, FileListResponse, etc.)
- Prefix unused destructured error vars with _ convention
- Fix prefer-const for summary variable
- Add _ ignore pattern to eslint.config.mjs
- Include test files in tsconfig.app.json to fix @testing-library/jest-dom types
- Resolve GitManagerModal.test.tsx merge conflict (take fn-1626 expectLatestCallStartsWith style)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/dashboard/app/styles.css

@@ -6369,6 +6369,12 @@ body {
   box-shadow: var(--shadow-sm);
 }
 
+@media (display-mode: standalone) {
+  #root {
+    padding-bottom: env(safe-area-inset-bottom, 0px);
+  }
+}
+
 /* === Mobile Responsive Overrides ===
    On narrow viewports (≤768px) the board switches from a 5-column grid to a
    horizontally-scrollable flex layout so only one scrollbar appears.  Each