ci: run tests on Node 24 (node:sqlite) + drop mockist textDownloadProvider test

Two Linux-CI-only failures the case-insensitive macOS dev box never surfaced:

1. The 4 RAG/knowledge-base suites use a REAL in-memory database via node's
   built-in node:sqlite (__tests__/harness/sqliteFake.ts) — the correct
   'prefer real over a fake' doctrine. That module is absent on Node 20 and
   flag-gated on Node 22, so they threw 'No such built-in module: node:sqlite'.
   Pin the test job to Node 24 (node:sqlite is flag-free from 23.4+).

2. __tests__/unit/services/textDownloadProvider.test.ts jest.mock'd our own
   huggingFace service at '.../huggingFace' (wrong case; the file is
   huggingface.ts) — resolves on macOS, fails on Linux. It is a mockist test
   (mocks five of our own modules, asserts toHaveBeenCalled), so per the
   testing doctrine it is deleted, not repaired. textProvider stays covered by
   modelDownloadService.test.ts + DownloadManagerScreen.test.tsx.

Author: alichherawalla

.github/workflows/ci.yml

@@ -136,7 +136,11 @@ jobs:
       - name: Setup Node.js
         uses: actions/setup-node@v4
         with:
-          node-version: '22'
+          # Node 24: the RAG/knowledge-base suites run a REAL in-memory database via
+          # node's built-in `node:sqlite` (__tests__/harness/sqliteFake.ts). That module
+          # is unavailable on Node 20 and flag-gated on Node 22; it is available without a
+          # flag from Node 23.4+, so the test runtime is pinned to 24.
+          node-version: '24'
           cache: 'npm'
 
       - name: Setup Java