Merge branch 'codex/simp-agent-entry-state' into codex/simp-unify-agent-session-id

# Conflicts:
#	docs/config-catalog.md
#	docs/cordis-catalog/services.md
#	docs/event-producer-consumer.md
#	docs/rfc/implemented/architecture/2026-06-18-agent-lifecycle-and-ownership-seams.md
#	docs/rfc/implemented/architecture/2026-06-20-branded-ids.md
#	docs/rfc/implemented/simplification/2026-06-20-remove-agent-boundary-mirror-events.md
#	docs/rfc/proposed/feature/2026-07-07-claude-code-and-codex-subagent-backends.md
#	docs/rfc/proposed/simplification/2026-06-20-unify-agent-and-session-id.md
#	packages/bash/tool-bash/README.md
#	packages/bash/tool-bash/src/index.ts
#	packages/bash/tool-bash/tests/tools.spec.ts
#	packages/core/agent-loop/README.md
#	packages/core/agent-loop/tests/properties.spec.ts
#	packages/core/agent/README.md
#	packages/core/agent/src/index.ts
#	packages/guard/repeat-tool-guard/src/index.ts
#	packages/hooks/hooks-claude/tests/bridge.spec.ts
#	packages/subagent/subagent-acp/tests/mock-acp-server.ts
#	packages/ui/acp/tests/dispose.spec.ts
#	packages/ui/stdio-agent/src/index.ts
#	packages/ui/stdio-agent/src/stdio-chat.ts
#	packages/ui/stdio-agent/tests/stdio-chat.spec.ts
#	packages/util/brand/src/index.ts

docs/core-data-structures/bash.md

@@ -108,7 +108,7 @@ interface BashExecSpec {
 
 The `owner` token is the isolation key: the executor stores it but never interprets it (access policy is the consumer's job), so a background task started by one agent isn't readable cross-session. A required-but-nullable field makes a forgotten owner a visible `undefined` rather than a silently-unowned task.
 
-`stdin` and `env` are set by in-process plugins (the hooks bridges, native plugins) to feed a hook command its JSON payload on stdin and its `CLAUDE_PROJECT_DIR`/`CLAUDE_PLUGIN_ROOT` env. The model-facing `dsh-tool-bash` tool does not expose them as parameters — its request is built from `command`/`workdir`/`timeoutMs`/`signal`/`owner` only — because a model already has equivalent power through shell syntax (`FOO=bar cmd`, a heredoc), so duplicating them as tool params would be redundant. This is NOT a security boundary: the credential scrub in `dsh-bash-local` is what stops the harness's ambient secrets reaching a spawned command, and it works regardless of these fields (a model cannot read a value the scrub removed, and tool-call args are static JSON, never shell-evaluated). A guard test asserts the tool doesn't forward model `env`/`stdin` — to catch a future `...args` spread, not to defend a trust wall. `env` is merged AFTER the scrub so an explicit caller entry (a value it already holds) wins even on a credential-shaped name. See [the bash-stdin-env RFC](../rfc/implemented/architecture/2026-06-30-bash-stdin-env-trusted-plugin-surface.md).
+Trusted in-process plugins use `stdin` and `env` for hook payloads and hook-specific variables. The model-facing bash tool constructs requests from its named schema fields and exposes neither input because shell syntax already provides equivalent power; tests guard against a future `...args` spread. This is request-shape discipline, not a security boundary: `dsh-bash-local` scrubs ambient credentials regardless of these fields, then overlays explicit values already held by the caller. See [the bash stdin/env RFC](../rfc/implemented/architecture/2026-06-30-bash-stdin-env-trusted-plugin-surface.md).
 
 Both ids the seam handles are [branded](core.md) (zero-cost `string` brands, the same machinery as `SessionId`): `BashTaskId` (a tracked background task, generated `bash-N` by the local executor) and `OwnerToken` (the opaque isolation key). `OwnerToken` is deliberately a DISTINCT brand from `SessionId`, not an alias: the bash seam is a capability seam that must not know what an owner token *means*, so it never imports `dsh-session`'s vocabulary — the `dsh-tool-bash` consumer is the single boundary that casts the owning agent's `SessionId` into an `OwnerToken`. Branding both stops a raw `string` (or a `BashTaskId` where an `OwnerToken` is expected, or vice versa) from slipping through the type checker on the model-facing `task_id` path.