fix: defer VS Code auto theme to platform

cli/src/__tests__/utils/theme-system.test.ts

@@ -0,0 +1,30 @@
+import { describe, expect, test } from 'bun:test'
+
+import { extractVSCodeTheme } from '../../utils/theme-system'
+
+describe('cli/utils/theme-system', () => {
+  describe('extractVSCodeTheme', () => {
+    test('uses explicit VS Code color theme when auto-detect is disabled', () => {
+      const theme = extractVSCodeTheme(`
+        {
+          "window.autoDetectColorScheme": false,
+          "workbench.colorTheme": "Default Light Modern"
+        }
+      `)
+
+      expect(theme).toBe('light')
+    })
+
+    test('defers to platform detection when VS Code syncs with OS theme', () => {
+      const theme = extractVSCodeTheme(`
+        {
+          "window.autoDetectColorScheme": true,
+          "workbench.preferredDarkColorTheme": "Default Dark Modern",
+          "workbench.preferredLightColorTheme": "Default Light Modern"
+        }
+      `)
+
+      expect(theme).toBeNull()
+    })
+  })
+})

cli/src/utils/theme-system.ts

@@ -321,39 +321,23 @@ const resolveZedSettingsPaths = (
   return paths
 }
 
-const extractVSCodeTheme = (content: string): ThemeName | null => {
-  // Try standard colorTheme setting
-  const colorThemeMatch = content.match(
-    /"workbench\.colorTheme"\s*:\s*"([^"]+)"/i,
-  )
-  if (colorThemeMatch) {
-    const inferred = inferThemeFromName(colorThemeMatch[1])
-    if (inferred) return inferred
-  }
-
-  // Check if auto-detect is enabled and try preferred themes
+export const extractVSCodeTheme = (content: string): ThemeName | null => {
   const autoDetectMatch = content.match(
     /"window\.autoDetectColorScheme"\s*:\s*(true|false)/i,
   )
   const autoDetectEnabled = autoDetectMatch?.[1]?.toLowerCase() === 'true'
 
   if (autoDetectEnabled) {
-    // Try to extract both preferred themes and infer from their names
-    const preferredDarkMatch = content.match(
-      /"workbench\.preferredDarkColorTheme"\s*:\s*"([^"]+)"/i,
-    )
-    if (preferredDarkMatch) {
-      const inferred = inferThemeFromName(preferredDarkMatch[1])
-      if (inferred) return inferred
-    }
+    return null
+  }
 
-    const preferredLightMatch = content.match(
-      /"workbench\.preferredLightColorTheme"\s*:\s*"([^"]+)"/i,
-    )
-    if (preferredLightMatch) {
-      const inferred = inferThemeFromName(preferredLightMatch[1])
-      if (inferred) return inferred
-    }
+  // Try standard colorTheme setting
+  const colorThemeMatch = content.match(
+    /"workbench\.colorTheme"\s*:\s*"([^"]+)"/i,
+  )
+  if (colorThemeMatch) {
+    const inferred = inferThemeFromName(colorThemeMatch[1])
+    if (inferred) return inferred
   }
 
   return null