feat: add desktop/web app package (#2606)

Co-authored-by: adamdotdevin <2363879+adamdottv@users.noreply.github.com>
Co-authored-by: Adam <2363879+adamdotdevin@users.noreply.github.com>
Co-authored-by: GitHub Action <action@github.com>

packages/app/src/context/theme.tsx

@@ -0,0 +1,92 @@
+import {
+  createContext,
+  useContext,
+  createSignal,
+  createEffect,
+  onMount,
+  type ParentComponent,
+  onCleanup,
+} from "solid-js"
+
+export interface ThemeContextValue {
+  theme: string | undefined
+  isDark: boolean
+  setTheme: (themeName: string) => void
+  setDarkMode: (isDark: boolean) => void
+}
+
+const ThemeContext = createContext<ThemeContextValue>()
+
+export const useTheme = () => {
+  const context = useContext(ThemeContext)
+  if (!context) {
+    throw new Error("useTheme must be used within a ThemeProvider")
+  }
+  return context
+}
+
+interface ThemeProviderProps {
+  defaultTheme?: string
+  defaultDarkMode?: boolean
+}
+
+const themes = ["opencode", "tokyonight", "ayu", "nord", "catppuccin"]
+
+export const ThemeProvider: ParentComponent<ThemeProviderProps> = (props) => {
+  const [theme, setThemeSignal] = createSignal<string | undefined>()
+  const [isDark, setIsDark] = createSignal(props.defaultDarkMode ?? false)
+
+  const handleKeyDown = (event: KeyboardEvent) => {
+    if (event.key === "t" && event.ctrlKey) {
+      event.preventDefault()
+      const current = theme()
+      if (!current) return
+      const index = themes.indexOf(current)
+      const next = themes[(index + 1) % themes.length]
+      setTheme(next)
+    }
+  }
+
+  onMount(() => {
+    window.addEventListener("keydown", handleKeyDown)
+  })
+
+  onCleanup(() => {
+    window.removeEventListener("keydown", handleKeyDown)
+  })
+
+  onMount(() => {
+    const savedTheme = localStorage.getItem("theme") ?? "opencode"
+    const savedDarkMode = localStorage.getItem("darkMode") ?? "true"
+    setIsDark(savedDarkMode === "true")
+    setTheme(savedTheme)
+  })
+
+  createEffect(() => {
+    const currentTheme = theme()
+    const darkMode = isDark()
+    if (currentTheme) {
+      document.documentElement.setAttribute("data-theme", currentTheme)
+      document.documentElement.setAttribute("data-dark", darkMode.toString())
+    }
+  })
+
+  const setTheme = async (theme: string) => {
+    setThemeSignal(theme)
+    localStorage.setItem("theme", theme)
+  }
+
+  const setDarkMode = (dark: boolean) => {
+    setIsDark(dark)
+    localStorage.setItem("darkMode", dark.toString())
+  }
+
+  const contextValue: ThemeContextValue = {
+    theme: theme(),
+    isDark: isDark(),
+    setTheme,
+    setDarkMode,
+  }
+
+  return <ThemeContext.Provider value={contextValue}>{props.children}</ThemeContext.Provider>
+}