[KM-476] [DED][FE] Knowledge (Document and DB) Flow Page

tikcet: https://bukittechnology.atlassian.net/browse/KM-476

- Implement connectDatabase, getDatabaseClientTypes, getDatabaseClients,
deleteDatabaseClient, and ingestDatabaseClient in api.ts with correct
request/response shapes per API contract
- Add DbTypeField, DbTypeInfo, DatabaseClient, and IngestResponse types;
remove placeholder PostgresCredentials and ConnectDatabaseResponse
- Replace hard-coded DB_TYPES with dynamic fetch from GET /dbtypes endpoint
- Add "Connection Name" required field to credentials form
- Render form fields dynamically from API schema (supports all db_type variants:
postgres, mysql, supabase, sqlserver, bigquery, snowflake)
- Refresh connection list from GET /database-clients/{user_id} after connect
to confirm persisted data from backend
- Add "Databases" section in main view listing connected clients with
Ingest and Delete actions per connection

.gitattributes

@@ -33,3 +33,6 @@ saved_model/**/* filter=lfs diff=lfs merge=lfs -text
 *.zip filter=lfs diff=lfs merge=lfs -text
 *.zst filter=lfs diff=lfs merge=lfs -text
 *tfevents* filter=lfs diff=lfs merge=lfs -text
+*.png filter=lfs diff=lfs merge=lfs -text
+*.svg filter=lfs diff=lfs merge=lfs -text
+*.jpg filter=lfs diff=lfs merge=lfs -text