feat(types): brand bash ids + stop brand erosion; extract Branded to dsh-brand

Type-only change (brands are zero-cost casts; no runtime/wire impact). Closes
the two gaps in the "brand ids that cross package boundaries" policy and fixes
the dependency direction so a capability package never pulls in an unrelated one.

- Extract the `Branded<B>` primitive into a new standalone type-only package
  `@deepseek-ai/dsh-brand` (packages/util/brand) with no harness-package deps.
  dsh-llm keeps its owned CallId but imports Branded from dsh-brand; dsh-session,
  dsh-agent, and dsh-bash all import Branded from there. dsh-bash depends on
  dsh-brand ALONE — never on dsh-llm or dsh-session (the architectural fix: a
  generic execution backend must not couple to the LLM or session vocabulary).
- Mint BashTaskId + OwnerToken in dsh-bash and thread them through BashTask.id,
  the get/ownerOf/list/readOutput/kill seam, the bash-local generation site, and
  the dsh-tool-bash validate/access surface. OwnerToken is a DISTINCT brand from
  SessionId so the seam stays decoupled; dsh-tool-bash is the single boundary
  that casts SessionId -> OwnerToken.
- Brand at the SOURCE, not via mid-pipeline casts: agent-loop's Config types
  agents[].id as AgentId and resumeSessionId as SessionId, so the brand enters
  at the config boundary and the inner create()/resume casts disappear (only the
  genuinely-new per-run session-id string is cast).
- Stop brand erosion: propagate CallId/SessionId/AgentId to the registry/store
  Map keys and public params/exports (SessionStore, AgentRegistry + factory
  options, the ACP session-id surface + ToolPresenter CallId map, the
  persistence coordinator, invariants pendingCalls, the pi-ai tool-call maps).
- Docs: document BashTaskId/OwnerToken in bash.md (type-equiv re-pasted), point
  the Branded type-equiv at dsh-brand, fix stale param types in the session/
  agent/bash READMEs, regenerate the cordis catalog + module graph.

Implements docs/rfc/proposed/architecture/2026-06-20-branded-ids.md

packages/bash/bash/tests/service.spec.ts

@@ -1,12 +1,12 @@
 import { describe, expect, it, vi } from 'vitest'
 import { Context } from 'cordis'
-import { BashExecutor } from '@deepseek-ai/dsh-bash'
+import { BashExecutor, BashTaskId, OwnerToken } from '@deepseek-ai/dsh-bash'
 import type { BashExecRequest, BashExecSpec, BashRunResult, BashTask, BashTaskRead } from '@deepseek-ai/dsh-bash'
 
 /** Minimal concrete executor: records calls, lets tests drive completions. */
 class StubExecutor extends BashExecutor {
-  tasks = new Map<string, BashTask>()
-  private owners = new Map<string, string | undefined>()
+  tasks = new Map<BashTaskId, BashTask>()
+  private owners = new Map<BashTaskId, OwnerToken | undefined>()
 
   resolve(request: BashExecRequest): BashExecSpec {
     return {
@@ -32,7 +32,7 @@ class StubExecutor extends BashExecutor {
 
   start(spec: BashExecSpec): BashTask {
     const task: BashTask = {
-      id: `stub-${this.tasks.size + 1}`,
+      id: BashTaskId(`stub-${this.tasks.size + 1}`),
       command: spec.command,
       status: 'running',
       exitCode: null,
@@ -44,11 +44,11 @@ class StubExecutor extends BashExecutor {
     return task
   }
 
-  get(id: string): BashTask | undefined {
+  get(id: BashTaskId): BashTask | undefined {
     return this.tasks.get(id)
   }
 
-  ownerOf(id: string): string | undefined {
+  ownerOf(id: BashTaskId): OwnerToken | undefined {
     return this.owners.get(id)
   }
 
@@ -56,13 +56,13 @@ class StubExecutor extends BashExecutor {
     return [...this.tasks.values()]
   }
 
-  readOutput(id: string): BashTaskRead {
+  readOutput(id: BashTaskId): BashTaskRead {
     const task = this.tasks.get(id)
     if (!task) throw new Error(`unknown bash task "${id}"`)
     return { task, delta: '', lossy: false }
   }
 
-  kill(id: string): boolean {
+  kill(id: BashTaskId): boolean {
     const task = this.tasks.get(id)
     if (!task) throw new Error(`unknown bash task "${id}"`)
     if (task.status !== 'running') return false