feat(rpc): add GetMoleculeProgress endpoint (bd-0oqz)

New RPC endpoint to get detailed progress for a molecule (parent issue
with child steps). Returns moleculeID, title, assignee, and list of
steps with their status (done/current/ready/blocked) and timestamps.

Used when user expands a worker in the activity feed TUI.

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

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

internal/storage/sqlite/blocked_cache.go

@@ -246,3 +246,22 @@ func (s *SQLiteStorage) rebuildBlockedCache(ctx context.Context, exec execer) er
 func (s *SQLiteStorage) invalidateBlockedCache(ctx context.Context, exec execer) error {
 	return s.rebuildBlockedCache(ctx, exec)
 }
+
+// GetBlockedIssueIDs returns all issue IDs currently in the blocked cache
+func (s *SQLiteStorage) GetBlockedIssueIDs(ctx context.Context) ([]string, error) {
+	rows, err := s.db.QueryContext(ctx, "SELECT issue_id FROM blocked_issues_cache")
+	if err != nil {
+		return nil, fmt.Errorf("failed to query blocked_issues_cache: %w", err)
+	}
+	defer rows.Close()
+
+	var ids []string
+	for rows.Next() {
+		var id string
+		if err := rows.Scan(&id); err != nil {
+			return nil, fmt.Errorf("failed to scan blocked issue ID: %w", err)
+		}
+		ids = append(ids, id)
+	}
+	return ids, rows.Err()
+}