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/session-persistence/session-persistence-sqlite/tests/sqlite.spec.ts

@@ -3,7 +3,7 @@ import { Context } from 'cordis'
 import { mkdtemp, rm } from 'node:fs/promises'
 import { tmpdir } from 'node:os'
 import { join } from 'node:path'
-import SessionStore from '@deepseek-ai/dsh-session'
+import SessionStore, { SessionId } from '@deepseek-ai/dsh-session'
 import type { Session, SessionEvent } from '@deepseek-ai/dsh-session'
 import SessionPersistenceSqlite, { SCHEMA_VERSION } from '@deepseek-ai/dsh-session-persistence-sqlite'
 import { openDatabase, scanRows, type EventRow } from '../src/schema.ts'
@@ -352,7 +352,7 @@ describe('SessionPersistenceSqlite: edge cases', () => {
     const path = await freshDbPath()
     // Instance 1 materializes a session and disposes.
     const b1 = await backend(path)
-    const s1 = b1.ctx.sessions.create('hmr-collide')
+    const s1 = b1.ctx.sessions.create(SessionId('hmr-collide'))
     for (const e of oneTurnLog()) s1.append(e.type, e.data)
     await b1.ctx.parallel('session/flush', s1)
     await b1.dispose()
@@ -363,7 +363,7 @@ describe('SessionPersistenceSqlite: edge cases', () => {
     await ctx.plugin(SessionStore)
     let session!: Session
     await ctx.plugin(Object.assign((inner: Context) => {
-      session = inner.sessions.create('hmr-collide')
+      session = inner.sessions.create(SessionId('hmr-collide'))
     }, { inject: ['sessions'] }))
     session.append('turn/start', { turn: 9, trigger: { kind: 'message', source: { kind: 'user' } } })
     await ctx.plugin(SessionPersistenceSqlite, { path })