refactor(subprocess): the dispose ladder moves to its one consumer

SubprocessHandle loses dispose(graces) and SubprocessDisposeGraces: the
stdin-EOF→SIGTERM→SIGKILL sequence is teardown POLICY encoding one
consumer's cooperation shape, not process vocabulary — the seam keeps
kill/terminate/waitForExit, and waitForExit(signal?) is the quiescence
probe a consumer ladder needs. dsh-subagent-acp owns disposeAcpChild()
over those public verbs (tier tests move into its suite; a never-exits
stub pins the fail-loud path); dsh-subprocess-local sheds the ladder,
its deadline import, and the dsh-timeout dependency. Every future
backend now owes four verbs and no teardown policy. New bilingual
ladder-ownership Agent Note records the decision; catalogs regenerated.

packages/subprocess/subprocess-local/package.json

@@ -29,13 +29,11 @@
   "peerDependencies": {
     "@deepseek-ai/dsh-invariants": "^0.0.1",
     "@deepseek-ai/dsh-subprocess": "^0.0.1",
-    "@deepseek-ai/dsh-timeout": "^0.0.1",
     "cordis": "^4.0.0-rc.7"
   },
   "devDependencies": {
     "@deepseek-ai/dsh-invariants": "workspace:^",
     "@deepseek-ai/dsh-subprocess": "workspace:^",
-    "@deepseek-ai/dsh-timeout": "workspace:^",
     "cordis": "^4.0.0-rc.7"
   }
 }