Merge latest master into subagent policy inheritance

Retarget the feature branch to the current master tip without rewriting its existing review history. Keeping this as a dedicated merge checkpoint makes the later simplification diff attributable to the stacked child rather than mixing base movement with design changes.

Resolve the identified-message API drift in the feature tests by constructing complete user messages, reading the nested tool-result message shape, and adapting the prompt-submit listener signature. Preserve both sides of the user-approval conflict: master’s createUserMessage wrapper and the feature’s inherited-policy attribution.

Regenerate the Cordis and persistence catalogs, re-record the session README pair, and refresh the affected ACP/headless fixtures so derived artifacts describe the merged source rather than either parent in isolation.

Validated with the focused policy/session/persistence/query suites (430 tests), focused ACP/headless snapshots (3 tests), build, doc-sync (25 gates), lint, hygiene, and git diff checks.

examples/headless-agent/tests/subagent-inheritance.snapshot.ts

@@ -18,6 +18,7 @@ import { fileURLToPath } from 'node:url'
 import { Context } from 'cordis'
 import { normalizeSessionLog, scrubRequestHeaders, type NormalizeContext } from '@deepseek-ai/dsh-acp-snapshot'
 import { LOADER_SMOKE_TEST_TIMEOUT_MS, runLoaderSmoke } from '@deepseek-ai/dsh-loader-smoke'
+import { createUserMessage } from '@deepseek-ai/dsh-llm'
 import SessionStore, { SESSION_FORMAT_VERSION, SessionId, type SessionEvent, type SessionHeader } from '@deepseek-ai/dsh-session'
 import SessionPersistenceJsonl from '@deepseek-ai/dsh-session-persistence-jsonl'
 import { describe, expect, it } from 'vitest'
@@ -52,7 +53,7 @@ async function seedReadOnlyParent(root: string, cwd: string): Promise<void> {
   }
   const events: SessionEvent[] = [
     { type: 'turn/start', seq: 0, time: 10, data: { turn: 1, trigger: { kind: 'message', source: { kind: 'user' } } } },
-    { type: 'user/message', seq: 1, time: 11, data: { content: [{ type: 'text', text: 'Tighten this session to read-only.' }], source: { kind: 'user' } }, surfaceOp: 'append' },
+    { type: 'user/message', seq: 1, time: 11, data: createUserMessage({ content: [{ type: 'text', text: 'Tighten this session to read-only.' }], source: { kind: 'user' } }), surfaceOp: 'append' },
     { type: 'sandbox/mode', seq: 2, time: 12, data: { mode: 'read-only' } },
     { type: 'turn/end', seq: 3, time: 13, data: { turn: 1, reason: { kind: 'completed' } } },
   ]