fix(rebase): migrate the replayed stack onto current master APIs

The linear replay carried each commit's own lineage, so this checkpoint
restores the master-owned surfaces the conflicted regions clobbered and
migrates branch-owned code to master's post-rebase APIs:

- rebuild subprocess-local spawn.ts on master's tree-exit-observer
  machinery, keeping the branch's win32 childEnv key semantics and the
  Linux zombie-quiescence probe; the zombie test reaps its survivor
  directly since a confirmed-absent verdict is a permanent
  no-more-signals boundary
- migrate pty-local test stubs to the Inbox-model Agent interface,
  Session.create, runnerFailureRules, and the new turn/start payload
- implement the seam's resolveExecutable/spawnTerminal abstracts in the
  new pwsh-local and tool-fs-search test fakes
- restore code-runtime, atomic-write, pwsh-local, and app-boot to
  master's exact content (the net-zero code-runtime churn is pruned
  from this history) and drop rename-detection graft debris
- re-apply the PR's architecture rows and execution-world paragraph,
  re-record bilingual pairings, regenerate catalogs, and reconcile the
  lockfile

packages/code-runtime/code-runtime-worker/README.md

@@ -34,7 +34,7 @@ Every field is validated and defaulted; `maxOutputBytes` is a safe integer of at
 
 Source mode loads erasable-only `src/worker.ts` through Node's native type stripping. Its transitive runtime closure contains only Node built-ins and relative source modules, so a fresh checkout never requires a sibling workspace package's unbuilt `lib/` export. The worker-local and session-owned JSON boundaries both flatten and rebuild validated values around the message port so application nesting never reaches structured clone. Built mode passes the sibling `lib/worker.cjs` as a filesystem path because pkg's VFS Worker hook expects CommonJS; the same path works under ordinary Node. The repository-wide requirement to exercise this published entry path belongs to the [testing policy](../../../docs/testing.md).
 
-The SDK surface is the default/named `WorkerCodeRuntime` class plus `Config`. The `./runtime-host` subpath shares type stripping, binding validation/dispatch, lossless JSON transport, and output accounting with sibling worker-based implementations; it is implementation support, not a plugin. The operational `./worker` subpath exists only as the packaged spawn entry; the wire protocol and bootstrap helpers remain source-private.
+The SDK surface is the default/named `WorkerCodeRuntime` class plus `Config`. The operational `./worker` subpath exists only as the packaged spawn entry; the wire protocol and bootstrap helpers are source-private implementation details.
 
 ## Model Experience
 

packages/code-runtime/code-runtime-worker/tests/runtime.spec.ts

@@ -597,27 +597,6 @@ describe('WorkerCodeRuntime — hostile programs (real workers)', () => {
     expect(result.value).toEqual({ name: 'ToolCallError', toolName: 'bad', message: 'binding resolution must be lossless JSON' })
   })
 
-  it('contains binding rejections whose thrown values cannot be rendered', async () => {
-    const { runtime } = await setup()
-    const result = await runtime.run({
-      program: 'try { await tools.bad({}) } catch (error) { return { name: error.name, toolName: error.toolName, message: error.message } }',
-      bindings: tools({
-        bad: async () => {
-          const hostile = new Error('hidden')
-          Object.defineProperty(hostile, 'message', {
-            get() { throw new Error('message getter failed') },
-          })
-          throw hostile
-        },
-      }),
-    })
-    expect(result.value).toEqual({
-      name: 'ToolCallError',
-      toolName: 'bad',
-      message: 'binding rejected with an unrenderable value',
-    })
-  })
-
   it('rejects lossy binding arguments in the worker before invoking the host binding', async () => {
     const { runtime } = await setup()
     let calls = 0