fix(acp): server crashed on connect — drop export default, read optional service cwd-independently

Two independent bugs made the ACP server crash the moment an editor (Zed)
connected, despite 178 green unit tests at 100% coverage:

1. `session/new` threw `cannot get property "agents" without inject`. Root
   cause: a stray `export default apply` made the cordis Loader's
   `unwrapExports` (`exports.default ?? exports`) collapse the module to the
   bare `apply` function, discarding the sibling `inject`/`name`/`Config`
   named exports. The plugin fiber was built with empty `inject`, so every
   `ctx.<service>` read in `apply` threw at load. Fix: remove the default
   export so the Loader uses the namespace.

2. `session/load` threw `cannot get property "sessionPersistence" without
   inject`. `AgentLoop.resume` read `this.ctx.sessionPersistence` (a service
   it deliberately does NOT inject); the property proxy's ancestor-only fiber
   walk fails through the bridge's traceable shadow. Fix: read it via
   `this.ctx.get('sessionPersistence', false)`, the topology-independent
   global-store lookup.

Why the suite missed both: every test mounted the plugin by hand
(`ctx.plugin({name,inject,apply})`), bypassing `unwrapExports` entirely, and
the only test driving these RPCs was key-gated (skipped in CI). Added a no-key
`session/new` e2e that boots the real example through the real Loader — it
fails loudly on bug #1 without an API key. Set `TSX_TSCONFIG_PATH` in the e2e
spawn so the subprocess resolves workspace `paths` from a temp cwd (it was
silently falling back to a stale built `lib/`).

Docs: post-mortem 0001; AGENTS.md "line coverage is not behavior coverage" +
with-key/smoke-test philosophy; packages/AGENTS.md plugin-export-shape and
ctx.get rules; dsh-code-review SKILL checks.

packages/acp/tests/dispose.spec.ts

@@ -38,7 +38,7 @@ describe('acp bridge — disposal & HMR safety', () => {
     // stay up and the transport is still live. A late session/new must hit the
     // `closed` guard and reject — NOT create an agent the disposed bridge can no
     // longer stream or settle. Verify the world: no agent appeared.
-    const harness = await makeBridgeHarness({ storageDir, script: [], childFiber: true })
+    const harness = await makeBridgeHarness({ storageDir, script: [] })
     await harness.client.initialize({ protocolVersion: PROTOCOL_VERSION, clientCapabilities: {} })
     const before = harness.ctx.agents.list().length
     await harness.acpFiber.dispose() // tear down ONLY the bridge

packages/acp/tests/harness.ts

@@ -146,8 +146,6 @@ export async function makeBridgeHarness(options: {
   script?: (StreamChunk[] | 'hang')[]
   config?: Partial<AcpConfig>
   storageDir: string
-  /** Mount the bridge in a disposable child fiber (for the ACP-only-HMR test). */
-  childFiber?: boolean
 } = { storageDir: '' }): Promise<BridgeHarness> {
   const adapter = new MockAdapter(options.script ?? [])
 
@@ -220,21 +218,20 @@ export async function makeBridgeHarness(options: {
   // override means "no model at all".
   const cfg: AcpConfig = { stream: agentStream, ...options.config }
   if (!(options.config && 'model' in options.config)) cfg.model = 'mock'
-  // By default apply the bridge directly on the root ctx (services ungated). For
-  // the ACP-only-HMR test, `childFiber: true` mounts it in a CHILD fiber instead
-  // so the test can dispose JUST the bridge while the rest of the harness stays
-  // up — its disposer (`harness.acpFiber.dispose()`) tears down only the
-  // bridge's listeners/effect. (Child-fiber service tracing gates the async
-  // persistence path, so the load-replay tests use the default direct mount.)
-  if (options.childFiber) {
-    harness.acpFiber = await ctx.plugin({
-      name: 'acp-test',
-      inject: ['agents', 'sessions', 'sessionPersistence'],
-      apply: (inner: Context) => { AcpPlugin.apply(inner, cfg) },
-    })
-  } else {
-    AcpPlugin.apply(ctx, cfg)
-  }
+  // Mount the bridge the way production does: as a cordis PLUGIN (via
+  // `ctx.plugin` with the real `inject`), NOT `AcpPlugin.apply(ctx, cfg)`
+  // directly on the root ctx. The plugin fiber is the faithful reproduction —
+  // the bridge's `apply` runs inside the fiber's injection scope, and its ACP
+  // handlers later run from the JSON-RPC read loop OUTSIDE that scope, exactly
+  // as under the example's cordis.yml. (Mounting directly on root made every
+  // service an ungated property and hid the "cannot get property … without
+  // inject" failure that bit a real Zed session.) `harness.acpFiber.dispose()`
+  // tears down JUST the bridge (its listeners + effect) for the HMR test.
+  harness.acpFiber = await ctx.plugin({
+    name: 'acp-test',
+    inject: ['agents', 'sessions', 'sessionPersistence'],
+    apply: (inner: Context) => { AcpPlugin.apply(inner, cfg) },
+  })
   harness.client = new ClientSideConnection(makeClient, clientStream)
 
   return harness