feat(v0.4.1): add config.SearchRoots for multi-root workspace lookup

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

internal/config/config.go

@@ -59,6 +59,35 @@ func ResolveProjectRoot() string {
 	return expandPath(v)
 }
 
+// SearchRoots returns the deduplicated list of workspace roots that all query
+// and listing operations must consult. Always includes CTASK_ROOT; also
+// includes CTASK_PROJECT_ROOT when set and different from CTASK_ROOT.
+func SearchRoots() []string {
+	taskRoot := ResolveRoot()
+	roots := []string{taskRoot}
+
+	projRoot := ResolveProjectRoot()
+	if projRoot == "" {
+		return roots
+	}
+
+	if samePath(taskRoot, projRoot) {
+		return roots
+	}
+	return append(roots, projRoot)
+}
+
+// samePath reports whether two absolute paths refer to the same directory
+// on the current platform. Uses case-insensitive compare on Windows.
+func samePath(a, b string) bool {
+	ac := filepath.Clean(a)
+	bc := filepath.Clean(b)
+	if runtime.GOOS == "windows" {
+		return strings.EqualFold(ac, bc)
+	}
+	return ac == bc
+}
+
 // EnvVars returns the environment variables to export into child sessions.
 // taskType must be "task" or "project"; an empty value defaults to "task".
 func EnvVars(slug, mode, root, workspace, category, taskType string) map[string]string {