feat(frontend): add opencode plugin types and API methods

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/lib/types.ts

@@ -885,6 +885,7 @@ export type FixActionKind =
   | "redownload_binary"
   | "retry_connection"
   | "open_agents_settings"
+  | "install_opencode_plugins"
 
 export interface FixAction {
   label: string
@@ -909,6 +910,32 @@ export interface PreflightResult {
   checks: CheckItem[]
 }
 
+// ─── OpenCode Plugins ───
+
+export type PluginStatus = "installed" | "missing"
+
+export interface PluginInfo {
+  name: string
+  declared_spec: string
+  installed_version: string | null
+  status: PluginStatus
+}
+
+export interface PluginCheckSummary {
+  config_path: string
+  cache_dir: string
+  plugins: PluginInfo[]
+  has_project_config_hint: boolean
+}
+
+export type PluginInstallEventKind = "started" | "log" | "completed" | "failed"
+
+export interface PluginInstallEvent {
+  task_id: string
+  kind: PluginInstallEventKind
+  payload: string
+}
+
 // ─── Chat Channels ───
 
 export type ChannelType = "lark" | "telegram" | "weixin"