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

packages/hooks/hooks-codex/tests/coverage.spec.ts

@@ -71,9 +71,8 @@ describe('hooks-codex coverage — decision mapping paths', () => {
   })
 
   it('a context-only UserPromptSubmit hook DELEGATES so a later listener can still block', async () => {
-    // Context alone is not a veto: a downstream agent/prompt-submit listener (a
-    // policy plugin registered after the bridge) must still get to block. The
-    // bridge delegates via next() and folds its context onto the decision.
+    // Context alone is not a veto: the bridge delegates with `next()` and folds its context, so a
+    // downstream policy listener can still block.
     const d = dir()
     hooks(d, { UserPromptSubmit: [{ hooks: [{ type: 'command', command: sh(d, 'c.sh', '#!/usr/bin/env bash\necho \'{"hookSpecificOutput":{"hookEventName":"UserPromptSubmit","additionalContext":"bridge ctx"}}\'\n') }] }] })
     const adapter = new MockAdapter([textResponse('should not run')])
@@ -439,11 +438,9 @@ describe('hooks-codex coverage — decision mapping paths', () => {
   })
 
   it('a NON-clean SessionStart hook (exit 2) does NOT inject its stdout as context', async () => {
-    // The plain-stdout→context fold is gated on exitCode === 0, matching the
-    // codec's structured-stdout rule. SessionStart is an EMIT (cannot block), so
-    // an `echo stale; exit 2` here is the exact case the gate guards: without it,
-    // the non-clean hook's stdout would wrongly inject "stale". A marker lets us
-    // wait for the detached hook to finish before asserting absence.
+    // SessionStart cannot block, but non-clean stdout still must not become context. The marker
+    // waits for detached completion; `echo stale; exit 2` then proves the exit-code gate matches
+    // the codec's structured-stdout rule.
     const d = dir()
     const marker = join(d, 'ran')
     hooks(d, { SessionStart: [{ hooks: [{ type: 'command', command: sh(d, 'b.sh', `#!/usr/bin/env bash\ntouch "${marker}"\necho "stale"\nexit 2\n`) }] }] })