fix(cli): honor local installation discovery precedence

tools/tht/internal/config/discovery.go

@@ -41,8 +41,8 @@ func Resolve(explicit string, environment func(string) string, workingDirectory
 		return "", errors.New("installation discovery could not resolve the current directory")
 	}
 
-	candidates := make(map[string]string)
 	for directory := filepath.Clean(start); ; directory = filepath.Dir(directory) {
+		candidates := make(map[string]string)
 		for _, path := range discoveryCandidates(directory) {
 			if hasArtifactsComponent(path) {
 				continue
@@ -57,6 +57,17 @@ func Resolve(explicit string, environment func(string) string, workingDirectory
 			canonical := canonicalPath(path)
 			candidates[canonical] = path
 		}
+		paths := make([]string, 0, len(candidates))
+		for _, path := range candidates {
+			paths = append(paths, path)
+		}
+		sort.Strings(paths)
+		if len(paths) == 1 {
+			return paths[0], nil
+		}
+		if len(paths) > 1 {
+			return "", fmt.Errorf("multiple valid installation descriptors found: %s; use --installation <absolute-path>/%s", formatCandidates(paths, root.Path), installationFileName)
+		}
 		if directory == root.Path {
 			break
 		}
@@ -66,19 +77,7 @@ func Resolve(explicit string, environment func(string) string, workingDirectory
 		}
 	}
 
-	paths := make([]string, 0, len(candidates))
-	for _, path := range candidates {
-		paths = append(paths, path)
-	}
-	sort.Strings(paths)
-	switch len(paths) {
-	case 1:
-		return paths[0], nil
-	case 0:
-		return "", fmt.Errorf("installation descriptor not found from %s; run tht setup or use --installation <absolute-path>/%s", filepath.Clean(friendlyRoot), installationFileName)
-	default:
-		return "", fmt.Errorf("multiple valid installation descriptors found: %s; use --installation <absolute-path>/%s", formatCandidates(paths, root.Path), installationFileName)
-	}
+	return "", fmt.Errorf("installation descriptor not found from %s; run tht setup or use --installation <absolute-path>/%s", filepath.Clean(friendlyRoot), installationFileName)
 }
 
 func formatCandidates(paths []string, root string) string {

tools/tht/internal/config/discovery_test.go

@@ -64,6 +64,44 @@ func TestResolveFindsDeployDescriptorFromNestedDirectory(t *testing.T) {
 	}
 }
 
+func TestResolveUsesLocalCandidateBeforeAncestorCandidate(t *testing.T) {
+	root := t.TempDir()
+	writeDiscoverableProject(t, root)
+	ancestor := writeDiscoverableInstallation(t, root, filepath.Join(root, "deploy", "ancestor"))
+	localDirectory := filepath.Join(root, "frontend", "feature")
+	local := writeDiscoverableInstallation(t, root, filepath.Join(localDirectory, "deploy", "local"))
+
+	got, err := Resolve("", func(string) string { return "" }, localDirectory)
+	if err != nil {
+		t.Fatal(err)
+	}
+	want, err := filepath.EvalSymlinks(local)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got != want {
+		t.Fatalf("Resolve() = %q, want local %q before ancestor %q", got, want, ancestor)
+	}
+}
+
+func TestResolveDiscoversDescriptorFromLinkedWorktree(t *testing.T) {
+	root := t.TempDir()
+	writeDiscoverableLinkedWorktree(t, root)
+	want := writeDiscoverableInstallation(t, root, filepath.Join(root, "deploy", "worktree"))
+
+	got, err := Resolve("", func(string) string { return "" }, filepath.Join(root, "frontend"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	canonicalWant, err := filepath.EvalSymlinks(want)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got != canonicalWant {
+		t.Fatalf("Resolve() = %q, want %q from linked worktree", got, canonicalWant)
+	}
+}
+
 func TestResolveIgnoresArtifactsAndRejectsAmbiguousValidCandidates(t *testing.T) {
 	root := t.TempDir()
 	writeDiscoverableProject(t, root)
@@ -112,13 +150,26 @@ func TestResolveDoesNotSearchAboveTheDiscoveredProjectRoot(t *testing.T) {
 }
 
 func writeDiscoverableProject(t *testing.T, root string) {
+	writeDiscoverableProjectWithGitMarker(t, root, false)
+}
+
+func writeDiscoverableLinkedWorktree(t *testing.T, root string) {
+	writeDiscoverableProjectWithGitMarker(t, root, true)
+}
+
+func writeDiscoverableProjectWithGitMarker(t *testing.T, root string, linkedWorktree bool) {
 	t.Helper()
 	for _, path := range []string{"backend", "frontend", "harness", "tools", "deploy"} {
 		if err := os.MkdirAll(filepath.Join(root, path), 0o755); err != nil {
 			t.Fatal(err)
 		}
 	}
-	if err := os.MkdirAll(filepath.Join(root, ".git"), 0o755); err != nil {
+	gitPath := filepath.Join(root, ".git")
+	if linkedWorktree {
+		if err := os.WriteFile(gitPath, []byte("gitdir: /tmp/thothii-worktree.git\n"), 0o600); err != nil {
+			t.Fatal(err)
+		}
+	} else if err := os.MkdirAll(gitPath, 0o755); err != nil {
 		t.Fatal(err)
 	}
 	if err := os.WriteFile(filepath.Join(root, "compose.yaml"), []byte("services: {}\n"), 0o600); err != nil {