feat: custom message types for system turns — wake and verdict messages

The custom-message scheme (user-decided 2026-09-12): system-authored
user-role messages are NOT human messages — they carry marker data parts
only, the adapter owns their model-facing wording, and the UI renders
them under control. Nothing fake is ever persisted as human speech.

The inventory (all migrated):
- probe→teacher handoff wake: was a text-bearing user message rendering
  as a fake user bubble; now data-probe-handoff marker-only — the
  adapter flattens it to HANDOFF_TEXT (core/contracts/chat.ts), the UI
  renders a quiet 'Preparing your plan…' system line.
- plan accept/decline: was boilerplate text ('The plan is accepted…',
  'I'd like the plan revised…') masquerading as learner speech — the
  decline wasn't even marked; now data-verdict {accepted, at} on its own
  message, adapter flattens to verdictText(), UI renders the quiet
  verdict marker ('✓ Plan accepted' / '↻ Plan revision requested').
  sendVerdict sends TWO REAL MESSAGES when the learner typed a note
  (the note as a genuine user message, then the verdict) in ONE turn
  via setMessages + sendMessage() — no 409 dance, no double teacher turn.
- sub-agent steers: the abort steer gains its data-subagent-aborted
  marker part; the UI keys steer rendering off PARTS (artifact/aborted),
  not metadata — metadata stays as pump mechanics only.
- record-adapter: systemTextOf() flattens marker-only messages; steers
  keep their text (payload — briefs are content, not boilerplate).

phases.ts: plan→teach advances on data-verdict{accepted:true} only;
learner text alone can never sanction teaching (pinned). data-plan-
accepted retired, no back-compat (user-decided: wiped-data doctrine).

Pinned: record-adapter.test.ts (verdict/handoff flattening, note+verdict
order, steer payload kept, UI-only parts skipped), phases.test.ts
(verdict marker semantics, out-of-order, text-never-fakes), jobs.test.ts
(abort marker part), demos.test.tsx (badge renders off the part, not
metadata).

Live GLM smoke (disposable driver, deleted): probe→conclude→wake→plan→
decline-with-note (revised, still plan)→accept-with-note (teach) — ALL
CHECKS PASS, including marker-only handoff/verdict on the wire and zero
fake human speech in the transcript.

Gates: tsc, lint, build, 335/335.

tests/demos.test.tsx

@@ -328,16 +328,20 @@ describe("steer card rendering (the delivered artifact)", () => {
 		assert.ok(!html.includes("Looking at the render"), "model-facing notes never render");
 	});
 
-	it("renders the abort chip for an aborted job's steer (2026-09 dock semantics)", () => {
+	it("renders the abort chip for an aborted job's steer (2026-09 dock semantics; the message type is the marker PART)", () => {
 		const steer = buildAbortSteer({ id: "jc", kind: "research", toolCallId: "cc" });
 		assert.equal(steer.metadata.subagentResult.aborted, true);
-		assert.equal(steer.parts.length, 1, "no artifact part on an abort");
+		assert.equal(steer.parts.length, 2, "text (teacher-facing) + the data-subagent-aborted marker part");
 		const html = renderToStaticMarkup(<SubagentSteerCard message={steer as never} />);
 		assert.match(html, /job-aborted-badge/);
 		assert.match(html, /research/, "the job's kind, lower-cased like the complete-badge idiom");
 		assert.match(html, /aborted by the learner/);
 		// the teacher-facing protocol text never renders for the learner
 		assert.ok(!html.includes("no brief is coming"), "no protocol glue in the chip");
+		// the badge renders off the PART, not metadata (the custom-message scheme)
+		const noMeta = { ...steer, metadata: {} } as typeof steer;
+		const htmlNoMeta = renderToStaticMarkup(<SubagentSteerCard message={noMeta as never} />);
+		assert.match(htmlNoMeta, /job-aborted-badge/, "metadata is pump mechanics, never the render seam");
 	});
 
 	it("renders a quiet Research-complete one-liner whose collapsed <details> carries the full brief", () => {