docs: require timestamp in AI log entries

- enforce YYYY-MM-DD HH:MM format in AI logs
- update AI BUILD ENTRY and AI PLAN ENTRY examples
- improve chronological accuracy of worklog

instructions-agent.md

@@ -143,7 +143,7 @@ Agents must write log entries using the following structure.
 Example for build tasks:
 
 ### AI BUILD ENTRY
-Date: YYYY-MM-DD  
+Date: YYYY-MM-DD HH:MM  
 Task: build  
 Objective: short description of the task
 
@@ -167,7 +167,7 @@ Open Issues:
 Example for plan tasks:
 
 ### AI PLAN ENTRY
-Date: YYYY-MM-DD  
+Date: YYYY-MM-DD HH:MM  
 Task: plan  
 Objective: short description of planning objective
 
@@ -187,3 +187,4 @@ Rules:
 - Do not include chain-of-thought reasoning.
 - Use bullet points when possible.
 - This format must be used when updating `docs/ai-worklog.md`.
+- The Date field must include both date and time using the format YYYY-MM-DD HH:MM.