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/bash/tool-bash/tests/integration.spec.ts

@@ -8,7 +8,7 @@ import SessionPersistenceJsonl from '@deepseek-ai/dsh-session-persistence-jsonl'
 import type { Agent } from '@deepseek-ai/dsh-agent'
 import AgentLoop from '@deepseek-ai/dsh-agent-loop'
 import { mountAgentLoopTestDependencies } from '@deepseek-ai/dsh-agent-loop-testkit'
-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 { LocalBashExecutor } from '@deepseek-ai/dsh-bash-local'
 import * as ToolBash from '@deepseek-ai/dsh-tool-bash'
@@ -27,7 +27,7 @@ async function harness(adapter: MockAdapter, sessionRoot?: string, dshHome?: str
     await ctx.plugin(SessionPersistenceJsonl, { root: sessionRoot, compression: 'none' })
   }
   await ctx.plugin(AgentLoop, { agents: [] })
-  await ctx.plugin(TaskService)
+  await ctx.plugin(LocalTaskService)
   await ctx.plugin(ToolTasks)
   await ctx.plugin(LocalBashExecutor, { timeoutMs: 10_000 })
   await ctx.plugin(ToolBash, dshHome === undefined ? {} : { dshHome })
@@ -169,7 +169,7 @@ describe('bash tool through the agent loop', () => {
   })
 
   it('background: start ack → completion notice as user/message → task_output collects it', async () => {
-    // The task id is deterministic (a fresh TaskService counts per kind from 1),
+    // The task id is deterministic (a fresh LocalTaskService counts per kind from 1),
     // so the script can name `bash-1` without threading a generated id.
     const adapter = new MockAdapter([
       toolCallResponse('call-1', 'bash', { command: 'echo bg-ok', description: 'test command', run_in_background: true }),