feat: terminology fix (Entry→Event), diary page generation, settings refactor

- Rename Entry→Event throughout frontend and backend
- Change 'journal' terminology to 'diary page'
- Add professional footer with links
- Redirect to diary page after generation
- Error handling for generation failures
- Fix settings to store per-provider configs in providerSettings
- Backend reads API key from providerSettings
- Use prisma db push instead of migrate for schema sync
- Clean up duplicate entries.ts file

backend/prisma/migrations/migration_lock.toml

@@ -0,0 +1,3 @@
+# Please do not edit this file manually
+# It should be added in your version-control system (e.g., Git)
+provider = "sqlite"