feat: team assignment on tickets + My team's tickets view

Backend:
- team_id column on tickets table
- team_id filter in GET /tickets (resolves team members)
- team_id in UpdateTicketSchema + PATCH handler
- SetTeam transaction type

Frontend:
- Team selector in ticket detail properties sidebar
- My team's tickets in sidebar (when user belongs to a team)
- team_id passed through to API from ticket list page

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/models/ticket.ts

@@ -15,6 +15,7 @@ export const UpdateTicketSchema = z.object({
   subject: z.string().min(1).optional(),
   status: z.string().min(1).optional(),
   owner_id: z.string().uuid().nullable().optional(),
+  team_id: z.string().uuid().nullable().optional(),
 });
 
 export const CommentSchema = z.object({