fix(theming): restore gruvbox as default via Default() helper

internal/modules/neovim/neovim.go

@@ -85,13 +85,10 @@ func nvimCfg() (string, error) {
 }
 
 func (m Module) resolvedTheme() string {
-	if t, ok := theming.Get(m.themeID); ok && t.NvChadTheme != "" {
+	if t, ok := theming.Get(m.themeID); ok {
 		return t.NvChadTheme
 	}
-	if list := theming.List(); len(list) > 0 && list[0].NvChadTheme != "" {
-		return list[0].NvChadTheme
-	}
-	return "gruvbox"
+	return theming.Default().NvChadTheme
 }
 
 // WriteChadrc renders chadrc.lua for the given NvChad theme name and writes

internal/modules/neovim/neovim_test.go

@@ -160,7 +160,7 @@ func TestPlanAfterApplyIsEmpty(t *testing.T) {
 	}
 }
 
-func TestUnknownThemeFallsBackToFirst(t *testing.T) {
+func TestUnknownThemeFallsBackToDefault(t *testing.T) {
 	home := t.TempDir()
 	t.Setenv("HOME", home)
 	r := &fakeRunner{installed: map[string]bool{"neovim": true}}
@@ -171,9 +171,8 @@ func TestUnknownThemeFallsBackToFirst(t *testing.T) {
 		t.Fatal(err)
 	}
 	chadrc, _ := os.ReadFile(filepath.Join(home, ".config", "nvim", "lua", "chadrc.lua"))
-	// Unknown theme IDs fall back to the first entry of theming.List(),
-	// which is sorted alphabetically by ID (currently "catppuccin").
-	if !strings.Contains(string(chadrc), `theme = "catppuccin"`) {
+	// Unknown theme IDs fall back to theming.Default(), which is gruvbox.
+	if !strings.Contains(string(chadrc), `theme = "gruvbox"`) {
 		t.Fatalf("fallback theme not applied: %s", chadrc)
 	}
 }

internal/theming/theming.go

@@ -97,6 +97,21 @@ func List() []Theme {
 	return out
 }
 
+// Default returns the archduino default theme. Used by the wizard's fresh-
+// install default and by callers that resolve an unknown theme ID.
+// The identity here is stable policy: gruvbox is the project's long-standing
+// default (carried over from the pre-Go installer). Changing this changes
+// the out-of-box experience on fresh systems.
+func Default() Theme {
+	if t, ok := Get("gruvbox"); ok {
+		return t
+	}
+	if len(discovered) > 0 {
+		return discovered[0]
+	}
+	return Theme{ID: "gruvbox", DisplayName: "Gruvbox Dark", NvChadTheme: "gruvbox"}
+}
+
 // Get returns the theme with the given ID, if present.
 func Get(id string) (Theme, bool) {
 	for _, t := range discovered {

internal/theming/theming_test.go

@@ -192,3 +192,9 @@ func TestApplyEachThemeWritesStarship(t *testing.T) {
 		})
 	}
 }
+
+func TestDefaultIsGruvbox(t *testing.T) {
+	if got := Default(); got.ID != "gruvbox" {
+		t.Fatalf("Default().ID = %q, want gruvbox", got.ID)
+	}
+}

internal/tui/state.go

@@ -54,10 +54,7 @@ func NewWizardState(cfg config.Config, reg *module.Registry) WizardState {
 	}
 	sort.Slice(choices, func(i, j int) bool { return choices[i].ID < choices[j].ID })
 
-	var theme string
-	if list := theming.List(); len(list) > 0 {
-		theme = list[0].ID
-	}
+	theme := theming.Default().ID
 	if override, ok := cfg.ThemeOverrides["__active"]; ok && override != "" {
 		theme = override
 	}

internal/tui/state_test.go

@@ -35,7 +35,7 @@ func TestNewWizardStatePreTicksAllByDefault(t *testing.T) {
 			t.Errorf("%s not selected", m.ID)
 		}
 	}
-	if s.ThemeID != theming.List()[0].ID {
+	if s.ThemeID != theming.Default().ID {
 		t.Errorf("theme = %q", s.ThemeID)
 	}
 }