feat(FN-3209): fix refine continuation flow in planning mode and add local

Merges fixes for the planning refine continuation flow (FN-3209) alongside a new local startup script for development environments. The changes include updates to `PlanningModeModal.tsx`, new and updated tests for the planning system, route handler improvements in `chat.ts` and `planning.ts`, and do

Fusion-Task-Id: FN-3209

docs/task-management.md

@@ -25,6 +25,7 @@ Use the 💡 button to open planning mode:
 - Break-into-tasks descriptions are structured with subtask-specific guidance first, then a separate larger-plan context section (plus `## Planning Interview Context` when interview history exists)
 - Sessions persist when the modal is closed — resume from the sidebar list at any time; reasoning context is restored automatically
 - Back navigation rewinds the server-side planning session to the previous answered question so you can revise earlier answers and continue from the corrected turn
+- On the summary screen, **Refine Further** continues through the backend planning session (including resumed completed sessions) and waits for a real follow-up question or updated summary; it does not switch to an empty question view
 
 ### 3) Todo item → Plan Mode