PR 30726 real-environment verification
main: 8b44f42b14c8e273156474a924ccf29680dd7857
PR: b7ad186e86f3afb62b3abeacf5c6055e077d9018
Linux; Playwright 1.60.0; /usr/bin/google-chrome

Started main with vp run dev --no-seed in /home/user/main.
Stopped its captured process group before starting PR with vp run dev --home-dir /home/user/t3code/.t3 --no-seed.
Created project /home/user/t3code through Add project > Local folder.
Used Codex gpt-6.1-sol through the web composer on both revisions.
Main provider turn: git rev-parse --show-toplevel and git status --short; completed, working tree clean.
PR provider turn: git rev-parse HEAD and git status --short; completed, exact PR SHA, working tree clean.

Reproduction: touch useTheme.ts without changing contents to trigger normal Vite HMR (?t= URL).
Fill the browser origin localStorage to its real quota, then click Settings > Appearance > Dark.
No mocked APIs, substituted Error objects, or edited application code.
Both revisions show the real save-failure toast and keep the previous appearance.

MAIN console.error attributes:
{
  "operation": "write",
  "storageKey": "t3code:theme-appearance-mode",
  "errorType": "error",
  "errorName": "ThemeStorageError",
  "errorTag": "ThemeStorageError",
  "stack": "    at writeAppearanceModePreference (http://localhost:8693/src/hooks/useTheme.ts)\n    at setAppearanceMode (http://localhost:8693/src/hooks/useTheme.ts)\n    at t13 (http://localhost:8693/src/components/settings/ThemeSettings.tsx:997:10)\n    at onClick (http://localhost:8693/src/components/settings/ThemeSettings.tsx:1062:22)\n    at executeDispatch (http://localhost:8693/node_modules/.vite/deps/client-CQQMupom.js)\n    at runWithFiberInDEV (http://localhost:8693/node_modules/.vite/deps/client-CQQMupom.js)\n    at processDispatchQueue (http://localhost:8693/node_modules/.vite/deps/client-CQQMupom.js)\n    at http://localhost:8693/node_modules/.vite/deps/client-CQQMupom.js\n    at batchedUpdates$1 (http://localhost:8693/node_modules/.vite/deps/client-CQQMupom.js)\n    at dispatchEventForPluginEventSystem (http://localhost:8693/node_modules/.vite/deps/client-CQQMupom.js)"
}

PR console.error attributes:
{
  "operation": "write",
  "storageKey": "t3code:theme-appearance-mode",
  "errorType": "error",
  "errorName": "ThemeStorageError",
  "errorTag": "ThemeStorageError",
  "stack": "    at writeAppearanceModePreference (http://localhost:5733/src/hooks/useTheme.ts:113:9)\n    at setAppearanceMode (http://localhost:5733/src/hooks/useTheme.ts:418:3)\n    at t13 (http://localhost:5733/src/components/settings/ThemeSettings.tsx:997:10)\n    at onClick (http://localhost:5733/src/components/settings/ThemeSettings.tsx:1062:22)\n    at executeDispatch (http://localhost:5733/node_modules/.vite/deps/client-CQQMupom.js:9659:5)\n    at runWithFiberInDEV (http://localhost:5733/node_modules/.vite/deps/client-CQQMupom.js:697:66)\n    at processDispatchQueue (http://localhost:5733/node_modules/.vite/deps/client-CQQMupom.js:9685:27)\n    at http://localhost:5733/node_modules/.vite/deps/client-CQQMupom.js:9954:5\n    at batchedUpdates$1 (http://localhost:5733/node_modules/.vite/deps/client-CQQMupom.js:1898:12)\n    at dispatchEventForPluginEventSystem (http://localhost:5733/node_modules/.vite/deps/client-CQQMupom.js:9758:4)"
}

Neighbor checks:
- Query-free ThemeSettings.tsx frames keep the same :997:10 and :1062:22 positions on both revisions.
- Query strings remain removed on PR.
- Remove only the quota-fill keys, click Dark again: localStorage appearance mode = dark, document class = dark.
- Reload: appearance mode and document class still dark.

Existing focused tests through blacksmith-check:
vp test run packages/client-runtime/src/errors/safeLog.test.ts
1 file passed; 2 tests passed. Includes credential/query/message redaction assertions.
CI: 31 successful, 0 failing, 0 pending at inspected head.

Unverified: native iOS/Android Metro frames; Firefox engine; Electron shell; remote/tunnel topology.
No source changes or pushes.