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/bash/pwsh-local/tests/executor.spec.ts

@@ -119,6 +119,8 @@ describe('spawn construction (pure, every platform)', () => {
   /** A subprocess service that records spawn specs and settles instantly. */
   class CapturingSubprocessService extends SubprocessService {
     specs: SubprocessSpawnSpec[] = []
+    override async resolveExecutable(command: string): Promise<string> { return command }
+    override spawnTerminal(): Promise<never> { throw new Error('pwsh spawns pipes, never terminals') }
     private readonly reader: SubprocessOutputReader = {
       readFrom: () => ({ text: '', lossy: false, nextOffset: 0 }),
     }

packages/bash/pwsh-local/tsconfig.json

@@ -18,19 +18,19 @@
       "path": "../../../vendor/schemastery"
     },
     {
-      "path": "../code-runtime"
+      "path": "../../util/brand"
     },
     {
-      "path": "../code-runtime-worker"
+      "path": "../../util/timeout"
+    },
+    {
+      "path": "../../bash/bash"
     },
     {
       "path": "../../subprocess/subprocess"
     },
     {
       "path": "../../support/invariants"
-    },
-    {
-      "path": "../../util/timeout"
     }
   ]
 }