fix desktop plugin startup without Bun

src/create-runtime-tmux-config.ts

@@ -1,6 +1,16 @@
 import type { OhMyOpenCodeConfig, TmuxConfig } from "./config"
 import { TmuxConfigSchema } from "./config/schema/tmux"
 
+type RuntimeWithBun = typeof globalThis & {
+  Bun?: {
+    which(binary: string): string | null
+  }
+}
+
+function defaultWhich(binary: string): string | null {
+  return (globalThis as RuntimeWithBun).Bun?.which(binary) ?? null
+}
+
 export function isTmuxIntegrationEnabled(
   pluginConfig: { tmux?: { enabled?: boolean } | undefined },
 ): boolean {
@@ -8,7 +18,7 @@ export function isTmuxIntegrationEnabled(
 }
 
 export function isInteractiveBashEnabled(
-  which: (binary: string) => string | null = Bun.which,
+  which: (binary: string) => string | null = defaultWhich,
 ): boolean {
   return which("tmux") !== null
 }