Merge remote-tracking branch 'origin/master' into xtr/agent-loop-message-machine

# Conflicts:
#	docs/architecture.i18n.yaml
#	docs/architecture.md
#	docs/architecture.zh.md
#	docs/core-data-structures/core.i18n.yaml

examples/acp-agent/tests/fixtures/subagent/subagent-acp/cordis.yml

@@ -10,6 +10,10 @@
 - id: subagent
   name: '@deepseek-ai/dsh-subagent'
 
+# The out-of-process ACP backend spawns its child through the subprocess seam.
+- id: subprocess
+  name: '@deepseek-ai/dsh-subprocess-local'
+
 - id: subagent-acp
   name: '@deepseek-ai/dsh-subagent-acp'
   config: