feat(skills): start-sprint marks actionable tickets in_progress

Step 7 now transitions all unblocked sprint tickets to in_progress
immediately rather than deferring to agents (who forget). Completes
the ticket lifecycle: start-sprint → in_progress, push-pr → review,
sprint stop → done.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.claude/skills/start-sprint/SKILL.md

@@ -131,18 +131,23 @@ db/connectors/ticket show <id>
 Read the decision files referenced in the sprint briefing so the agent has
 full architectural context before starting work.
 
-### 7. Present the work plan
+### 7. Mark tickets in progress and present the work plan
 
-Output a summary:
+Mark all actionable (unblocked, non-done) tickets in the sprint as
+`in_progress`:
+
+```bash
+db/connectors/ticket status <id> in_progress
+```
+
+Then output a summary:
 - Sprint name and goal
 - Branch status (clean merge or conflicts)
-- Actionable tickets (unblocked, ready to start)
+- Tickets marked in_progress (list with IDs)
 - Blocked tickets (and what blocks them)
 - Key decisions loaded
 - Suggested first task (lowest ID unblocked ticket)
 
-Do NOT mark any ticket as `in_progress` yet.
-
 ### 8. Confirm and spawn the team
 
 Before spawning agents, use `AskUserQuestion` to confirm the work plan and