feat: Complete key:value format implementation and fix tag sync

Implement complete key:value format parsing for change log entries and fix
critical tag synchronization issue from server to client.

Key Changes:

1. Shared Key:Value Parser (NEW: internal/engine/parser.go)
   - Created ParseKeyValueFormat() for both edit and sync operations
   - Supports flexible whitespace: 'key:value' and 'key: value'
   - Handles comment skipping for edit files
   - Consolidates parsing logic (DRY principle)

2. Database Triggers - Tags Support (internal/engine/database.go)
   - Added tags to track_task_create trigger
   - Added tags to track_task_update trigger
   - Tags sorted alphabetically via SQL ORDER BY
   - Format: 'tags: alpha,bravo,charlie'

3. Task Creation - Tag Update Fix (internal/engine/task.go)
   - CreateTaskWithModifier() now triggers update after adding tags
   - Ensures tags appear in change log (UPDATE entry)
   - Fixes missing tags in initial CREATE entries

4. Edit Command - Use Shared Parser (cmd/edit.go)
   - Replaced custom parseEditedFile() with shared ParseKeyValueFormat()
   - Added tag sorting in parseTags()
   - Removed ~30 lines, improved maintainability

5. Sync Client - Complete Implementation (internal/sync/client.go)
   - NEW: applyChangeDataToTask() - parses all fields from change log
   - NEW: Helper functions for status, priority, tag parsing
   - FIXED: parseChanges() - sort by timestamp+ID before grouping
   - Added parent/child task ordering (prevents FK violations)
   - Enhanced tag sync in merge loop with task reload
   - Specific validation error messages per field

Critical Bug Fix:
- When CREATE and UPDATE have same timestamp, old code kept CREATE (no tags)
- New code sorts by ID as tiebreaker, ensuring UPDATE (with tags) is used
- Verified: Server->client tag sync now works correctly

Validation:
- Description must not be empty (both edit and sync)
- Recurrence validated (not negative, max 100 years)
- All timestamps parsed correctly (Unix epoch)
- Tags sorted alphabetically in all contexts

Testing:
- Fresh pull from server: ✅ All tags present
- API-created tasks: ✅ Tags sync correctly
- Local->server->client round-trip: ✅ No data loss
- Same-second CREATE+UPDATE: ✅ Correct entry processed
- Parent/child tasks: ✅ Correct ordering

Files Changed:
- NEW: internal/engine/parser.go (+44 lines)
- Modified: internal/engine/database.go (+10 lines)
- Modified: internal/engine/task.go (+8 lines)
- Modified: cmd/edit.go (-25 lines net)
- Modified: internal/sync/client.go (+280 lines)
- Modified: srv/README.md (+1 line)

Total: +318 lines added, -25 removed, net +293 lines

This completes Phase 6: Full bidirectional sync with complete tag support.

opal-task/internal/engine/database.go

@@ -214,7 +214,12 @@ func runMigrations() error {
 						CASE WHEN NEW.wait IS NOT NULL THEN 'wait: ' || NEW.wait || CHAR(10) ELSE '' END ||
 						CASE WHEN NEW.until_date IS NOT NULL THEN 'until: ' || NEW.until_date || CHAR(10) ELSE '' END ||
 						CASE WHEN NEW.recurrence_duration IS NOT NULL THEN 'recurrence: ' || NEW.recurrence_duration || CHAR(10) ELSE '' END ||
-						CASE WHEN NEW.parent_uuid IS NOT NULL THEN 'parent_uuid: ' || NEW.parent_uuid || CHAR(10) ELSE '' END
+						CASE WHEN NEW.parent_uuid IS NOT NULL THEN 'parent_uuid: ' || NEW.parent_uuid || CHAR(10) ELSE '' END ||
+						(SELECT CASE WHEN COUNT(*) > 0 
+							THEN 'tags: ' || GROUP_CONCAT(tag, ',') || CHAR(10)
+							ELSE '' 
+						END 
+						FROM (SELECT tag FROM tags WHERE task_id = NEW.id ORDER BY tag))
 					);
 				END;
 
@@ -248,7 +253,12 @@ func runMigrations() error {
 						CASE WHEN NEW.wait IS NOT NULL THEN 'wait: ' || NEW.wait || CHAR(10) ELSE '' END ||
 						CASE WHEN NEW.until_date IS NOT NULL THEN 'until: ' || NEW.until_date || CHAR(10) ELSE '' END ||
 						CASE WHEN NEW.recurrence_duration IS NOT NULL THEN 'recurrence: ' || NEW.recurrence_duration || CHAR(10) ELSE '' END ||
-						CASE WHEN NEW.parent_uuid IS NOT NULL THEN 'parent_uuid: ' || NEW.parent_uuid || CHAR(10) ELSE '' END
+						CASE WHEN NEW.parent_uuid IS NOT NULL THEN 'parent_uuid: ' || NEW.parent_uuid || CHAR(10) ELSE '' END ||
+						(SELECT CASE WHEN COUNT(*) > 0 
+							THEN 'tags: ' || GROUP_CONCAT(tag, ',') || CHAR(10)
+							ELSE '' 
+						END 
+						FROM (SELECT tag FROM tags WHERE task_id = NEW.id ORDER BY tag))
 					);
 				END;
 

opal-task/internal/engine/parser.go

@@ -0,0 +1,43 @@
+package engine
+
+import (
+	"fmt"
+	"strings"
+)
+
+// ParseKeyValueFormat parses key:value format from text
+// Each line should be "key:value" or "key: value" (whitespace trimmed)
+// If skipComments=true, lines starting with # are ignored
+// Empty lines are always skipped
+func ParseKeyValueFormat(data string, skipComments bool) (map[string]string, error) {
+	fields := make(map[string]string)
+	lines := strings.Split(data, "\n")
+
+	for i, line := range lines {
+		// Trim whitespace
+		line = strings.TrimSpace(line)
+
+		// Skip empty lines
+		if line == "" {
+			continue
+		}
+
+		// Skip comments if requested
+		if skipComments && strings.HasPrefix(line, "#") {
+			continue
+		}
+
+		// Split on first ':'
+		parts := strings.SplitN(line, ":", 2)
+		if len(parts) != 2 {
+			return nil, fmt.Errorf("line %d: invalid format (expected 'key:value')", i+1)
+		}
+
+		key := strings.TrimSpace(parts[0])
+		value := strings.TrimSpace(parts[1])
+
+		fields[key] = value
+	}
+
+	return fields, nil
+}

opal-task/internal/engine/task.go

@@ -173,6 +173,14 @@ func CreateTaskWithModifier(description string, mod *Modifier) (*Task, error) {
 				return nil, err
 			}
 		}
+
+		// Update task to trigger change log with tags
+		if len(mod.AddTags) > 0 {
+			task.Modified = timeNow()
+			if err := task.Save(); err != nil {
+				return nil, err
+			}
+		}
 	}
 
 	return task, nil