Add artist/performer information to videos and admin interface

Update database schema and admin UI to include an 'artist' field for videos, and configure agent integrations for database access.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 170e18f0-0f13-4eca-8643-546bba1dd8cc
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/8cc42625-c1f5-4e43-99bd-77f2c4dedee2/170e18f0-0f13-4eca-8643-546bba1dd8cc/QfqdFa4

shared/schema.ts

@@ -10,6 +10,7 @@ export const genreEnum = pgEnum('genre', ['volksmusik', 'schlager', 'pop', 'rock
 export const videos = pgTable("videos", {
   id: varchar("id").primaryKey().default(sql`gen_random_uuid()`),
   title: text("title").notNull(),
+  artist: text("artist"), // Izvajalec/Artist name
   description: text("description").default("").notNull(),
   thumbnailUrl: text("thumbnail_url").notNull(),
   customThumbnailUrl: text("custom_thumbnail_url"),