chore(db): drop legacy copilot_chats.messages JSONB column (#4886)

Reads and writes are fully cut over to the normalized copilot_messages table
(verified in production: no writes to the column in 24h, recently-active chats
have empty JSONB while copilot_messages holds the transcript). Drop the dead
column via drizzle migration 0225 and re-type CopilotChatDetailRow.messages as
an assembled (non-column) field.

Deploy notes: reconcile any chats where the JSONB still leads copilot_messages
before applying, and pg_repack copilot_chats afterward to reclaim the ~5.7GB
TOAST storage (DROP COLUMN is metadata-only).

Author: waleedlatif1

apps/sim/lib/copilot/chat/lifecycle.ts

@@ -101,12 +101,14 @@ export type CopilotChatDetailRow = Pick<
   | 'workspaceId'
   | 'type'
   | 'title'
-  | 'messages'
   | 'conversationId'
   | 'resources'
   | 'createdAt'
   | 'updatedAt'
->
+> & {
+  /** Transcript assembled from `copilot_messages` (no longer a chat-row column). */
+  messages: unknown[]
+}
 
 export type CopilotChatLegacyDetailRow = CopilotChatDetailRow &
   Pick<typeof copilotChats.$inferSelect, 'model' | 'planArtifact' | 'config'>

packages/db/migrations/0225_greedy_ares.sql

@@ -0,0 +1 @@
+ALTER TABLE "copilot_chats" DROP COLUMN "messages";