refactor(tasks): split the task registry into seam and local implementation

The tasks/ family now matches the capability-seam shape: @deepseek-ai/dsh-tasks
keeps the abstract TaskService (ctx.tasks contract, vocabulary types, snapshot
invariant companion) and the new @deepseek-ai/dsh-tasks-local carries the
process-local registry (LocalTaskService: in-memory store, settlement,
owner-cleanup effects, teardown, TASK_WAIT_TIMEOUT). Compositions and test
harnesses now load dsh-tasks-local; producers, TaskKindMap merges, and
dsh-tool-tasks keep importing the seam only.

Producer misconfiguration diagnostics name dsh-tasks-local because loading the
implementation is the fix. The registry behavior suite moves to tasks-local;
the seam keeps a stub-subclass registration test and the probe-based invariant
suite.

packages/pty/tool-pty/package.json

@@ -54,6 +54,7 @@
     "@deepseek-ai/dsh-session": "workspace:^",
     "@deepseek-ai/dsh-system-prompt": "workspace:^",
     "@deepseek-ai/dsh-tasks": "workspace:^",
+    "@deepseek-ai/dsh-tasks-local": "workspace:^",
     "@deepseek-ai/dsh-tool-tasks": "workspace:^",
     "@deepseek-ai/dsh-tools": "workspace:^",
     "cordis": "^4.0.0-rc.7"

packages/pty/tool-pty/src/index.ts

@@ -250,7 +250,7 @@ export function apply(ctx: Context, config: Config = {}): void {
       if (args.run_in_background === true) {
         if (!enableRunInBackground) throw new Error('background terminal sends are disabled by tool-pty configuration')
         const tasks = ctx.get('tasks')
-        if (tasks === undefined) throw new Error('background terminal sends require @deepseek-ai/dsh-tasks and @deepseek-ai/dsh-tool-tasks')
+        if (tasks === undefined) throw new Error('background terminal sends require @deepseek-ai/dsh-tasks-local and @deepseek-ai/dsh-tool-tasks')
         let cancelRequested = false
         const taskId = tasks.start({
           kind: 'pty-send',

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

@@ -9,7 +9,7 @@ import ToolRegistry, { renderToolsSdk } from '@deepseek-ai/dsh-tools'
 import type { ToolSdkSchema } from '@deepseek-ai/dsh-tools/src/ts-types.ts'
 import PtyService, { PtySessionId } from '@deepseek-ai/dsh-pty'
 import type { PtyBackend, PtyBackendSession, PtySendOperation, PtySendRequest, PtySessionStatus, PtySignal } from '@deepseek-ai/dsh-pty'
-import TaskService from '@deepseek-ai/dsh-tasks'
+import LocalTaskService from '@deepseek-ai/dsh-tasks-local'
 import * as ToolTasks from '@deepseek-ai/dsh-tool-tasks'
 import * as ToolPty from '@deepseek-ai/dsh-tool-pty'
 
@@ -106,7 +106,7 @@ async function setupBase(tasks: boolean) {
   const stub = stubBackend()
   ctx.pty.registerBackend(stub.backend)
   if (tasks) {
-    await ctx.plugin(TaskService)
+    await ctx.plugin(LocalTaskService)
     await ctx.plugin(ToolTasks)
   }
   return { ctx, stub, agent: fakeAgent(ctx, tasks ? 'with-tasks' : 'foreground') }