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.

scripts/gen-tool-catalog.ts

@@ -29,7 +29,7 @@ import SubagentService from '@deepseek-ai/dsh-subagent'
 import type { SubagentProvider } from '@deepseek-ai/dsh-subagent'
 import SkillService from '@deepseek-ai/dsh-skill'
 import * as SkillLocal from '@deepseek-ai/dsh-skill-local'
-import TaskService from '@deepseek-ai/dsh-tasks'
+import LocalTaskService from '@deepseek-ai/dsh-tasks-local'
 import * as ToolAskUser from '@deepseek-ai/dsh-tool-ask-user'
 import * as ToolBash from '@deepseek-ai/dsh-tool-bash'
 import * as ToolCordis from '@deepseek-ai/dsh-tool-cordis'
@@ -355,7 +355,7 @@ const TOOL_PACKAGES: ToolPackage[] = [
     requires: ['ctx.tools', 'ctx.tasks', 'ctx.systemPrompt'],
     writes: ['tool/call', 'tool/result', 'user/message via agent.inject() for background completion notices'],
     async mount(ctx) {
-      await ctx.plugin(TaskService)
+      await ctx.plugin(LocalTaskService)
       await ctx.plugin(ToolTasks)
     },
     note: