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/src/index.ts

@@ -2,10 +2,9 @@
  * The subprocess seam (`ctx.subprocess`): spawn fully-specified commands into
  * managed process trees with Node-shaped stdio dispositions — raw pipes for
  * protocol streams, inherit for diagnostics, bounded spill-backed collection
- * for batch output — plus tree-scoped signalling and a cooperative dispose
- * ladder. Command defaulting, shell semantics, deadlines, framing, and
- * presentation belong to consumers; the bash executor seam is the owning
- * template. The local implementation lives in
+ * for batch output — plus tree-scoped signalling. Command defaulting, shell
+ * semantics, deadlines, teardown ladders, framing, and presentation belong to
+ * consumers; the bash executor seam is the owning template. The local implementation lives in
  * `@deepseek-ai/dsh-subprocess-local`.
  * @module @deepseek-ai/dsh-subprocess
  */
@@ -22,7 +21,6 @@ export type {
   DshEnvironmentKey,
   SubprocessCollect,
   SubprocessCollectedOutputs,
-  SubprocessDisposeGraces,
   SubprocessHandle,
   SubprocessOutcome,
   SubprocessOutputMode,
@@ -102,10 +100,11 @@ declare module 'cordis' {
  *   readers never consume one another's output; lossy reads report truncation
  *   and the spill file holding the complete stream when one exists. Piped
  *   streams are handed to the caller raw and never buffered here.
- * - {@link SubprocessHandle.kill} signals without escalation,
+ * - {@link SubprocessHandle.kill} signals without escalation, and
  *   {@link SubprocessHandle.terminate} (and the spec's abort signal) escalates
- *   SIGTERM→grace→SIGKILL, and {@link SubprocessHandle.dispose} runs the
- *   cooperative EOF-first ladder — all tree-scoped on every platform.
+ *   SIGTERM→grace→SIGKILL — both tree-scoped on every platform.
+ *   {@link SubprocessHandle.waitForExit} observes whole-tree liveness, so a
+ *   consumer-owned teardown ladder can hold each tier on real quiescence.
  * - Disposal of the service terminates all still-running managed processes
  *   and awaits their exit.
  */

packages/subprocess/subprocess/src/types.ts

@@ -160,30 +160,6 @@ export interface SubprocessCollectedOutputs {
   readonly stderr?: SubprocessOutputReader
 }
 
-/**
- * The two grace periods of the cooperative dispose ladder
- * ({@link SubprocessHandle.dispose}). Consumers carry them as defaulted,
- * validated Config fields, so teardown timing is deployment-tunable and this
- * seam hardcodes nothing.
- */
-export interface SubprocessDisposeGraces {
-  /**
-   * Tier-1 window (ms): after stdin EOF, how long the child gets to quiesce
-   * ON ITS OWN — flush durable state, tear down its own descendants — before
-   * escalation to platform termination. Usually WIDER than
-   * {@link SubprocessDisposeGraces.graceMs}: a cooperative child's EOF-driven
-   * teardown may itself wait on a signal-trapping grandchild plus a final
-   * flush.
-   */
-  eofGraceMs: number
-  /**
-   * Termination confirmation window (ms): POSIX applies it after `SIGTERM`
-   * and again after `SIGKILL`; Windows applies it after the forced tree
-   * termination.
-   */
-  graceMs: number
-}
-
 /**
  * A live child process rooted in its own process tree. Collected output
  * remains readable after exit; piped streams belong to the caller.
@@ -226,13 +202,4 @@ export interface SubprocessHandle {
    * @returns `true` when the tree exited, `false` when the signal aborted first.
    */
   waitForExit(signal?: AbortSignal): Promise<boolean>
-  /**
-   * Tear the child down to quiescence, resolving only after exit: close stdin
-   * (when this handle owns a piped one) and allow cooperative flush for
-   * `eofGraceMs`, then SIGTERM with a `graceMs` window (POSIX), then forced
-   * tree termination with a final bounded `graceMs` wait.
-   * @param graces - the ladder's two windows, from the consumer's Config.
-   * @throws when the child still has not exited `graceMs` after the forced tier.
-   */
-  dispose(graces: SubprocessDisposeGraces): Promise<void>
 }