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).

packages/bash/tool-bash/tests/tools.spec.ts

@@ -17,7 +17,7 @@ import * as ToolTasks from '@deepseek-ai/dsh-tool-tasks'
 import ApprovalService from '@deepseek-ai/dsh-user-approval'
 import type { ApprovalOutcome } from '@deepseek-ai/dsh-user-approval'
 import { LocalBashExecutor } from '@deepseek-ai/dsh-bash-local'
-import LocalProcessManager from '@deepseek-ai/dsh-process-local'
+import LocalSubprocessService from '@deepseek-ai/dsh-subprocess-local'
 import SandboxPolicyService from '@deepseek-ai/dsh-sandbox-policy'
 import * as ToolBash from '@deepseek-ai/dsh-tool-bash'
 import { processOutcome } from '../src/background.ts'
@@ -33,8 +33,8 @@ async function setup() {
   await ctx.plugin(SystemPrompt)
   await ctx.plugin(ToolRegistry)
   await ctx.plugin(AgentRegistry)
-  await ctx.plugin(LocalProcessManager)
-  ;(ctx.processes as LocalProcessManager).internals = { spillDir }
+  await ctx.plugin(LocalSubprocessService)
+  ;(ctx.subprocess as LocalSubprocessService).internals = { spillDir }
   await ctx.plugin(LocalBashExecutor, { timeoutMs: 10_000, graceMs: 200 })
   await ctx.plugin(ToolBash)
   return ctx
@@ -48,8 +48,8 @@ async function setupWithTasks() {
   await ctx.plugin(AgentRegistry)
   await ctx.plugin(LocalTaskService)
   await ctx.plugin(ToolTasks)
-  await ctx.plugin(LocalProcessManager)
-  ;(ctx.processes as LocalProcessManager).internals = { spillDir }
+  await ctx.plugin(LocalSubprocessService)
+  ;(ctx.subprocess as LocalSubprocessService).internals = { spillDir }
   await ctx.plugin(LocalBashExecutor, { timeoutMs: 10_000, graceMs: 200 })
   await ctx.plugin(ToolBash)
   return ctx
@@ -278,8 +278,8 @@ describe('bash tool', () => {
     const ctx = new Context()
     await ctx.plugin(SystemPrompt)
     await ctx.plugin(ToolRegistry)
-    await ctx.plugin(LocalProcessManager)
-    ;(ctx.processes as LocalProcessManager).internals = { spillDir }
+    await ctx.plugin(LocalSubprocessService)
+    ;(ctx.subprocess as LocalSubprocessService).internals = { spillDir }
     await ctx.plugin(LocalBashExecutor, { maxOutputBytes: 100, graceMs: 200 })
     await ctx.plugin(ToolBash)
     const result = await call(ctx, 'bash', { command: 'for i in $(seq 1 100); do printf "line-%04d\\n" $i; done', description: 'test command' })
@@ -387,7 +387,7 @@ describe('bash tool', () => {
     const ctx = new Context()
     await ctx.plugin(SystemPrompt)
     await ctx.plugin(ToolRegistry)
-    await ctx.plugin(LocalProcessManager)
+    await ctx.plugin(LocalSubprocessService)
     await ctx.plugin(LocalBashExecutor, {})
     const fiber = await ctx.plugin(ToolBash)
     expect(ctx.tools.schemas()).toHaveLength(1)
@@ -405,7 +405,7 @@ describe('bash tool', () => {
     // inject: ['tools', 'bash'] keeps the plugin pending until bash exists.
     await ctx.plugin(ToolBash)
     expect(ctx.tools.schemas()).toHaveLength(0)
-    await ctx.plugin(LocalProcessManager)
+    await ctx.plugin(LocalSubprocessService)
     await ctx.plugin(LocalBashExecutor, {})
     await new Promise(resolve => setTimeout(resolve, 0))
     expect(ctx.tools.schemas()).toHaveLength(1)
@@ -417,7 +417,7 @@ describe('bash tool', () => {
     const ctx = new Context()
     await ctx.plugin(SystemPrompt)
     await ctx.plugin(ToolRegistry)
-    await ctx.plugin(LocalProcessManager)
+    await ctx.plugin(LocalSubprocessService)
     await ctx.plugin(LocalBashExecutor, {})
     ToolBash.apply(ctx, {})
     const schema = ctx.tools.schemas()[0]!
@@ -533,7 +533,7 @@ describe('background execution through the task runtime', () => {
     const ctx = new Context()
     await ctx.plugin(SystemPrompt)
     await ctx.plugin(ToolRegistry)
-    await ctx.plugin(LocalProcessManager)
+    await ctx.plugin(LocalSubprocessService)
     await ctx.plugin(LocalBashExecutor, {})
     await ctx.plugin(ToolBash, { enableRunInBackground: false })