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/cordis/tool-cordis/src/api-catalog.ts

@@ -2221,13 +2221,9 @@ export const TYPE_API: readonly TypeApiEntry[] = [
     name: 'SubprocessCollectedOutputs',
     declaration: 'export interface SubprocessCollectedOutputs {\n    readonly stdout?: SubprocessOutputReader;\n    readonly stderr?: SubprocessOutputReader;\n}',
   },
-  {
-    name: 'SubprocessDisposeGraces',
-    declaration: 'export interface SubprocessDisposeGraces {\n    eofGraceMs: number;\n    graceMs: number;\n}',
-  },
   {
     name: 'SubprocessHandle',
-    declaration: 'export interface SubprocessHandle {\n    readonly pid: number;\n    readonly stdin: Writable | undefined;\n    readonly stdout: Readable | undefined;\n    readonly stderr: Readable | undefined;\n    readonly collected: SubprocessCollectedOutputs;\n    readonly done: Promise<SubprocessOutcome>;\n    kill(signal?: NodeJS.Signals): void;\n    terminate(): void;\n    waitForExit(signal?: AbortSignal): Promise<boolean>;\n    dispose(graces: SubprocessDisposeGraces): Promise<void>;\n}',
+    declaration: 'export interface SubprocessHandle {\n    readonly pid: number;\n    readonly stdin: Writable | undefined;\n    readonly stdout: Readable | undefined;\n    readonly stderr: Readable | undefined;\n    readonly collected: SubprocessCollectedOutputs;\n    readonly done: Promise<SubprocessOutcome>;\n    kill(signal?: NodeJS.Signals): void;\n    terminate(): void;\n    waitForExit(signal?: AbortSignal): Promise<boolean>;\n}',
   },
   {
     name: 'SubprocessOutcome',