feat(opencode): Windows PowerShell installer and Desktop key file

CLI and Desktop share %USERPROFILE%\.config\opencode. Persist the API
key in .arka-api-key so GUI apps do not need a login-shell export.

opencode/plugins/arka-ai.ts

@@ -6,9 +6,35 @@ const PROVIDER_ID = "Arka-AI"
 const API_URL = "https://api.arka-ai.ru/v1"
 const CATALOG_URL =
   "https://git.arka-ai.ru/arka/public/raw/branch/main/opencode/catalog.json"
-const CACHE_FILE = join(homedir(), ".cache", "opencode", "arka-ai-models.json")
 const TTL_MS = 24 * 60 * 60 * 1000
 
+function configDir(): string {
+  const xdg = process.env.XDG_CONFIG_HOME
+  if (xdg) return join(xdg, "opencode")
+  return join(homedir(), ".config", "opencode")
+}
+
+function cacheDir(): string {
+  const xdg = process.env.XDG_CACHE_HOME
+  if (xdg) return join(xdg, "opencode")
+  return join(homedir(), ".cache", "opencode")
+}
+
+const CACHE_FILE = join(cacheDir(), "arka-ai-models.json")
+const KEY_FILE = join(configDir(), ".arka-api-key")
+
+function readApiKey(): string | undefined {
+  const fromEnv = process.env.ARKA_API_KEY?.trim()
+  if (fromEnv) return fromEnv
+  try {
+    if (existsSync(KEY_FILE)) {
+      const fromFile = readFileSync(KEY_FILE, "utf8").trim()
+      if (fromFile) return fromFile
+    }
+  } catch {}
+  return undefined
+}
+
 // Ids that must always be exposed, even if the filter would drop them.
 const FORCED_MODELS = [
   "DeepSeek-V4-Pro",
@@ -50,7 +76,7 @@ function loadCache(): Cache | null {
 
 function saveCache(models: ModelMap): void {
   try {
-    mkdirSync(join(homedir(), ".cache", "opencode"), { recursive: true })
+    mkdirSync(cacheDir(), { recursive: true })
     writeFileSync(CACHE_FILE, JSON.stringify({ ts: Date.now(), models }))
   } catch {}
 }
@@ -99,7 +125,7 @@ async function resolveModels(): Promise<ModelMap | null> {
   } catch {}
 
   try {
-    const key = process.env.ARKA_API_KEY
+    const key = readApiKey()
     const json = await fetchJson(
       `${API_URL}/models`,
       key ? { Authorization: `Bearer ${key}` } : {},
@@ -115,6 +141,7 @@ async function resolveModels(): Promise<ModelMap | null> {
 
 export default async function ArkaAIProviderPlugin() {
   const models = await resolveModels()
+  const apiKey = readApiKey()
 
   return {
     config: (cfg: any) => {
@@ -124,12 +151,18 @@ export default async function ArkaAIProviderPlugin() {
       // Static models from opencode.json act as a fallback; the fetched
       // catalog is layered on top so the configured default model never
       // disappears even if the catalog drops it.
+      // apiKey from env or ~/.config/opencode/.arka-api-key so Desktop /
+      // Windows GUI works without a login-shell export.
       cfg.provider[PROVIDER_ID] = {
         name: "Arka-AI",
         api: API_URL,
         env: ["ARKA_API_KEY"],
         ...prev,
         models: { ...(prev.models ?? {}), ...(models ?? {}) },
+        options: {
+          ...(prev.options ?? {}),
+          ...(apiKey ? { apiKey } : {}),
+        },
       }
     },
   }