Update agent_runs types for code generation workflow

- Make message_id optional (nullable)
- Add user_id field for tracking who initiated the run
- Support agent_runs created directly from n8n workflow

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/types/database.ts

@@ -184,8 +184,9 @@ export interface Database {
       agent_runs: {
         Row: {
           id: string
-          message_id: string
+          message_id: string | null
           project_id: string
+          user_id: string | null
           command: string
           status: 'pending' | 'running' | 'completed' | 'failed' | 'cancelled'
           result: Json | null
@@ -207,8 +208,9 @@ export interface Database {
         }
         Insert: {
           id?: string
-          message_id: string
+          message_id?: string | null
           project_id: string
+          user_id?: string
           command: string
           status?: 'pending' | 'running' | 'completed' | 'failed' | 'cancelled'
           result?: Json | null