Merge branch 'claude/electron-offline-design' into dev

Encrypted SQLite/FTS5 offline search index for the Electron desktop
client: event-driven reindex (mail, calendar, contacts, files) driven
off the existing JMAP push connection, per-account keys held in OS
keychain via safeStorage, search API returns ranked context ready for
an LLM/RAG prompt.

.gitignore

@@ -38,6 +38,14 @@ yarn-error.log*
 # vercel
 .vercel
 
+# electron (see electron/, scripts/build-electron.mjs, electron-builder.config.js)
+/dist-electron/
+/dist-electron-builds/
+
+# playwright output
+/test-results/
+/playwright-report/
+
 # typescript
 *.tsbuildinfo
 next-env.d.ts