fix(desktop): resolve durable bridge state

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Copilot-Session: 1fc19188-72f7-45c9-9cb3-fc3aad38a17c

Author: SlowGreekMSFT

packages/core/src/copilot-bridge.ts

@@ -20,6 +20,14 @@ export const defaultStaleTTL = 7 * 24 * 60 * 60 * 1000
 export const defaultContextLimit = 128_000
 export const defaultOutputLimit = 32_000
 
+export function resolveStateDirectory(home: string, environment: NodeJS.ProcessEnv = process.env) {
+  return (
+    environment[stateDirectoryEnvironment] ??
+    environment.COPILOT_BRIDGE_STATE_DIR ??
+    path.join(home, ".copilot", "opencode-copilot-bridge-state")
+  )
+}
+
 export class InvalidURLError extends Schema.TaggedErrorClass<InvalidURLError>()("CopilotBridge.InvalidURL", {
   url: Schema.String,
   message: Schema.String,
@@ -308,15 +316,7 @@ export function config(stateDirectory: string): Config {
 
 export const configLayer = Layer.effect(
   ConfigService,
-  Global.Service.use((global) =>
-    Effect.succeed(
-      config(
-        process.env[stateDirectoryEnvironment] ??
-          process.env.COPILOT_BRIDGE_STATE_DIR ??
-          path.join(global.state, "copilot-bridge"),
-      ),
-    ),
-  ),
+  Global.Service.use((global) => Effect.succeed(config(resolveStateDirectory(global.home)))),
 )
 
 export const configNode = makeGlobalNode({

packages/core/test/copilot-bridge.test.ts

@@ -52,6 +52,23 @@ async function fixture(fetch: (request: Request) => Response | Promise<Response>
 }
 
 describe("CopilotBridge descriptor authentication", () => {
+  test("resolves the durable state directory for normal desktop launches", () => {
+    expect(CopilotBridge.resolveStateDirectory("/Users/test", {})).toBe(
+      "/Users/test/.copilot/opencode-copilot-bridge-state",
+    )
+    expect(
+      CopilotBridge.resolveStateDirectory("/Users/test", {
+        OPENCODE_COPILOT_BRIDGE_STATE_DIR: "/private/opencode",
+        COPILOT_BRIDGE_STATE_DIR: "/private/bridge",
+      }),
+    ).toBe("/private/opencode")
+    expect(
+      CopilotBridge.resolveStateDirectory("/Users/test", {
+        COPILOT_BRIDGE_STATE_DIR: "/private/bridge",
+      }),
+    ).toBe("/private/bridge")
+  })
+
   test("accepts only literal HTTP loopback /v1 endpoints", () => {
     expect(CopilotBridge.baseURL("http://127.0.0.1:4142/v1/")).toBe("http://127.0.0.1:4142/v1")
     expect(() => CopilotBridge.baseURL("https://127.0.0.1:4142/v1")).toThrow()