feat: Add mol_type schema field for molecule type classification (bd-oxgi)

Add mol_type field to beads for swarm coordination:
- Values: 'swarm' (multi-polecat), 'patrol' (recurring ops), 'work' (default)
- Nullable, defaults to empty string (treated as 'work')

Changes:
- Add mol_type column to SQLite schema and migration 031
- Add MolType type with IsValid() validation in types.go
- Update insertIssue/GetIssue to handle mol_type
- Add --mol-type flag to create command
- Add mol_type filtering to list and ready commands
- Update RPC protocol for daemon mode support
- Update test schema in migrations_test.go

🤝 Generated with [Claude Code](https://claude.com/claude-code)

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

internal/storage/sqlite/ready.go

@@ -106,6 +106,12 @@ func (s *SQLiteStorage) GetReadyWork(ctx context.Context, filter types.WorkFilte
 		args = append(args, *filter.ParentID)
 	}
 
+	// Molecule type filtering
+	if filter.MolType != nil {
+		whereClauses = append(whereClauses, "i.mol_type = ?")
+		args = append(args, string(*filter.MolType))
+	}
+
 	// Build WHERE clause properly
 	whereSQL := strings.Join(whereClauses, " AND ")