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

docs/module-graph.md

@@ -7,11 +7,15 @@ Inter-package dependencies among the `@deepseek-ai/dsh-*` harness packages, deri
 
 ```mermaid
 graph TD
+  bash --> brand
+  llm --> brand
   bash-local --> bash
   llm-deepseek --> llm
   llm-pi-ai --> llm
+  session --> brand
   session --> llm
   system-prompt --> llm
+  agent --> brand
   agent --> llm
   agent --> session
   llm-replay --> llm
@@ -49,14 +53,15 @@ graph TD
 
 | Package | Depends on |
 | --- | --- |
-| `bash` | — |
-| `llm` | — |
+| `brand` | — |
+| `bash` | `brand` |
+| `llm` | `brand` |
 | `bash-local` | `bash` |
 | `llm-deepseek` | `llm` |
 | `llm-pi-ai` | `llm` |
-| `session` | `llm` |
+| `session` | `brand`, `llm` |
 | `system-prompt` | `llm` |
-| `agent` | `llm`, `session` |
+| `agent` | `brand`, `llm`, `session` |
 | `llm-replay` | `llm`, `session` |
 | `session-persistence` | `session` |
 | `invariants` | `agent`, `llm`, `session` |