feat: add precise timestamps for session correlation

Update timestamp format in ctx add commands for better session correlation:

- Tasks now include #added:YYYY-MM-DD-HHMM tag
- Learnings use YYYY-MM-DD-HHMM (was YYYY-MM-DD)
- Decisions use YYYY-MM-DD-HHMM (was YYYY-MM-DD)

This enables correlating context entries to sessions by timestamp overlap,
helping trace when decisions/learnings were added.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: josealekhine

.context/TASKS.md

@@ -131,9 +131,9 @@
 - `#in-progress` — currently being worked on (add inline, don't move task)
 
 ### Phase 12: Timestamp-Based Session Correlation `#priority:medium` `#area:cli`
-- [ ] Add timestamp to formatTask() in add.go — currently tasks have no timestamp, add `#added:YYYY-MM-DD-HHMM` or similar
-- [ ] Increase timestamp precision in formatLearning() — change from YYYY-MM-DD to YYYY-MM-DD-HHMM
-- [ ] Increase timestamp precision in formatDecision() — change from YYYY-MM-DD to YYYY-MM-DD-HHMM
+- [x] Add timestamp to formatTask() in add.go — currently tasks have no timestamp, add `#added:YYYY-MM-DD-HHMM` or similar
+- [x] Increase timestamp precision in formatLearning() — change from YYYY-MM-DD to YYYY-MM-DD-HHMM
+- [x] Increase timestamp precision in formatDecision() — change from YYYY-MM-DD to YYYY-MM-DD-HHMM
 - [ ] Add start_time field to session summary files — record when session began
 - [ ] Add last_update_time field to session summary files — update on each ctx add call during session
 - [ ] Document timestamp correlation approach in AGENT_PLAYBOOK.md — explain how to correlate entries to sessions by time overlap

internal/cli/add.go

@@ -111,7 +111,8 @@ func runAdd(cmd *cobra.Command, args []string) error {
 }
 
 func formatDecision(content string) string {
-	date := time.Now().Format("2006-01-02")
+	// Use YYYY-MM-DD-HHMM for precise timestamp correlation with sessions
+	timestamp := time.Now().Format("2006-01-02-1504")
 	return fmt.Sprintf(`## [%s] %s
 
 **Status**: Accepted
@@ -123,20 +124,23 @@ func formatDecision(content string) string {
 **Rationale**: [Add rationale here]
 
 **Consequences**: [Add consequences here]
-`, date, content, content)
+`, timestamp, content, content)
 }
 
 func formatTask(content string, priority string) string {
+	// Use YYYY-MM-DD-HHMM timestamp for session correlation
+	timestamp := time.Now().Format("2006-01-02-1504")
 	var priorityTag string
 	if priority != "" {
 		priorityTag = fmt.Sprintf(" #priority:%s", priority)
 	}
-	return fmt.Sprintf("- [ ] %s%s\n", content, priorityTag)
+	return fmt.Sprintf("- [ ] %s%s #added:%s\n", content, priorityTag, timestamp)
 }
 
 func formatLearning(content string) string {
-	date := time.Now().Format("2006-01-02")
-	return fmt.Sprintf("- **[%s]** %s\n", date, content)
+	// Use YYYY-MM-DD-HHMM for precise timestamp correlation with sessions
+	timestamp := time.Now().Format("2006-01-02-1504")
+	return fmt.Sprintf("- **[%s]** %s\n", timestamp, content)
 }
 
 func formatConvention(content string) string {