refactor(subprocess): rename the process seam to subprocess and address review

Review feedback (tianyicui): 'process' is a poor service name. The family is
now packages/subprocess/ — @deepseek-ai/dsh-subprocess (ctx.subprocess,
abstract SubprocessService, Subprocess* vocabulary) and
@deepseek-ai/dsh-subprocess-local (LocalSubprocessService) — renamed
throughout code, compositions, docs (en+zh, pairs re-recorded), catalogs,
and gates. 'subprocess' is the precise term for managed OS children (the
Python-stdlib sense), avoids colliding with Node's global process object,
and reads as one system beside dsh-subagent-subprocess.

ds-review-bot findings addressed:
- kill() on a settled handle is now a no-op (no signal to a possibly-reused
  pgid, no referenced grace timer delaying exit); pinned by a spy test.
- The moved DshEnvironmentKey/DshEnvironment/CollectedOutput types get
  drift-checked type-equiv blocks on the new subprocess.md page, restoring
  their manifest registration.
- subprocess.md is registered in the core.md sub-page index (en+zh).

docs/cordis-catalog/services.md

@@ -257,7 +257,7 @@ Implementations must honor these semantics:
 - run rejects only for infrastructure failures. Nonzero exits, timeout kills, and abort kills resolve with a BashRunResult.
 - start returns immediately; no timeout applies to background processes. `done` settles at process close and never rejects; spawn failures settle as `killed` with the error on stderr.
 - BashProcess.readOutput is incremental: consecutive reads never repeat output. Lossy reads report truncation and available spill files.
-- A still-running background process is stopped and awaited when its owning composition tears down. With the process-manager seam that boundary is `ctx.processes` disposal, so a background process survives an executor-only reload.
+- A still-running background process is stopped and awaited when its owning composition tears down. With the subprocess seam that boundary is `ctx.subprocess` disposal, so a background process survives an executor-only reload.
 
 ```ts cordis-catalog
 /**
@@ -315,7 +315,7 @@ collect(execution: ToolExecution): DshEnvironment
 list(): BashEnvVariableInfo[]
 ```
 
-Types: [DshEnvironment](../core-data-structures/process.md) · [ToolExecution](../core-data-structures/tools.md)
+Types: [DshEnvironment](../core-data-structures/subprocess.md) · [ToolExecution](../core-data-structures/tools.md)
 
 Source: [`packages/bash/tool-bash/src/index.ts:104`](../../packages/bash/tool-bash/src/index.ts)
 
@@ -829,31 +829,6 @@ Types: [Agent](../core-data-structures/core.md)
 
 Source: [`packages/plan/plan-mode/src/index.ts:141`](../../packages/plan/plan-mode/src/index.ts)
 
-## `ctx.processes` — `ProcessManager` (abstract seam)
-
-Abstract process manager. Subclass, implement spawn, and load the subclass as a plugin — it registers as `ctx.processes` (one implementation per context; loading a second throws, which is cordis' standard duplicate-service behavior).
-
-Implementations must honor these semantics:
-
-- spawn returns immediately with a live handle; `done` resolves at process close and rejects only for spawn-level failures.
-- Output readers are offset-based and non-consuming, so independent readers never consume one another's output; lossy reads report truncation and the spill file holding the complete stream when one exists.
-- ProcessHandle.kill and the spec's abort signal escalate SIGTERM→grace→SIGKILL across the whole process group.
-- Disposal kills all still-running managed processes and awaits their exit.
-
-```ts cordis-catalog
-/**
- * Start one managed child process from a fully-specified spec; this seam
- * applies no defaults.
- * @param spec - argv, directory, limits, grace, cancellation, and environment.
- * @returns the live process handle (readers, kill, outcome promise).
- */
-abstract spawn(spec: ProcessSpawnSpec): ProcessHandle
-```
-
-Types: [ProcessHandle](../core-data-structures/process.md) · [ProcessSpawnSpec](../core-data-structures/process.md)
-
-Source: [`packages/process/process/src/index.ts:48`](../../packages/process/process/src/index.ts)
-
 ## `ctx.pty` — `PtyService`
 
 In-process registry for replaceable PTY backends and exact-Agent sessions.
@@ -1584,6 +1559,31 @@ Types: [SubagentProvider](../core-data-structures/subagent.md) · [SubagentRun](
 
 Source: [`packages/subagent/subagent/src/index.ts:180`](../../packages/subagent/subagent/src/index.ts)
 
+## `ctx.subprocess` — `SubprocessService` (abstract seam)
+
+Abstract subprocess service. Subclass, implement spawn, and load the subclass as a plugin — it registers as `ctx.subprocess` (one implementation per context; loading a second throws, which is cordis' standard duplicate-service behavior).
+
+Implementations must honor these semantics:
+
+- spawn returns immediately with a live handle; `done` resolves at process close and rejects only for spawn-level failures.
+- Output readers are offset-based and non-consuming, so independent readers never consume one another's output; lossy reads report truncation and the spill file holding the complete stream when one exists.
+- SubprocessHandle.kill and the spec's abort signal escalate SIGTERM→grace→SIGKILL across the whole process group.
+- Disposal kills all still-running managed processes and awaits their exit.
+
+```ts cordis-catalog
+/**
+ * Start one managed child process from a fully-specified spec; this seam
+ * applies no defaults.
+ * @param spec - argv, directory, limits, grace, cancellation, and environment.
+ * @returns the live process handle (readers, kill, outcome promise).
+ */
+abstract spawn(spec: SubprocessSpawnSpec): SubprocessHandle
+```
+
+Types: [SubprocessHandle](../core-data-structures/subprocess.md) · [SubprocessSpawnSpec](../core-data-structures/subprocess.md)
+
+Source: [`packages/subprocess/subprocess/src/index.ts:48`](../../packages/subprocess/subprocess/src/index.ts)
+
 ## `ctx.systemPrompt` — `SystemPrompt`
 
 Registry service for the prompt inputs assembled before each model step.