opencode/run: refresh themes after terminal reloads (#30917)

packages/opencode/test/cli/tui/theme-store.test.ts

@@ -1,6 +1,7 @@
 import { expect, test } from "bun:test"
+import type { TerminalColors } from "@opentui/core"
 
-const { DEFAULT_THEMES, allThemes, addTheme, hasTheme, resolveTheme } = await import(
+const { DEFAULT_THEMES, allThemes, addTheme, hasTheme, resolveTheme, terminalMode } = await import(
   "../../../src/cli/cmd/tui/context/theme"
 )
 
@@ -49,3 +50,27 @@ test("resolveTheme rejects circular color refs", () => {
 
   expect(() => resolveTheme(item, "dark")).toThrow("Circular color reference")
 })
+
+function terminalColors(defaultBackground: string | null, palette: Array<string | null> = []): TerminalColors {
+  return {
+    palette,
+    defaultForeground: null,
+    defaultBackground,
+    cursorColor: null,
+    mouseForeground: null,
+    mouseBackground: null,
+    tekForeground: null,
+    tekBackground: null,
+    highlightBackground: null,
+    highlightForeground: null,
+  }
+}
+
+test("terminalMode derives mode from refreshed background", () => {
+  expect(terminalMode(terminalColors("#fbf1c7"))).toBe("light")
+  expect(terminalMode(terminalColors("#1a1b26"))).toBe("dark")
+})
+
+test("terminalMode does not derive mode from ANSI slot zero", () => {
+  expect(terminalMode(terminalColors(null, ["#000000"]))).toBeUndefined()
+})