refactor: update delivery status templates for clarity and consistency

backend/templates/BOARD_MEMORY.md.j2

@@ -5,30 +5,7 @@
 Durable facts and decisions only.
 No daily logs. No secrets.
 
-## Current Delivery Status
-
-### Objective
-(TODO)
-
-### Current State
-- State: Working | Blocked | Waiting | Done
-- Last updated: (YYYY-MM-DD HH:MM {{ user_timezone or "UTC" }})
-
-### Plan (3-7 steps)
-1. (TODO)
-2. (TODO)
-
-### Last Progress
-- (TODO)
-
-### Next Step (exactly one)
-- (TODO)
-
-### Blocker (if any)
-- (TODO)
-
-### Evidence
-- (TODO)
+{% include "BOARD_DELIVERY_STATUS.md.j2" %}
 
 ## Durable decisions
 - YYYY-MM-DD: (decision) — (rationale)