two questions per teaching unit: predict → teach → check (owner 2026-10-03)

The teaching cycle gains its motivation question. The teach quiz schema
now carries a REQUIRED type field — predict (posed before the teaching,
arrives open, the learner predicts the next step) or check (posed after,
arrives collapsed behind the reveal). The prober's quiz stays role-less.

- core: quizInputObject.type union + normalizeQuizType + the reveal law
  as pure quizNeedsReveal; QuestionData.questionType; note → thinking
  rename (legacy reads fold back); readingThinking channel on answers;
  compactAnswerForModel emits thinking / thinkingWhileReading
- tools: descriptions stripped to mechanics — QUIZ_OPTION_CRAFT and
  EXPLAIN_DOCTRINE deleted, doctrine moved to the prompt layer
  (reverses the 2026-09-27 placement, owner 2026-10-03); shared
  quizDescription/explainDescription builders differ only in deltas
- prompts: shared/20-question-tools.md rewritten (option craft,
  transcribed-speech leniency, the two thinking channels); new
  teacher/28-predictions.md (cycle, roles, skip rule, resolution law);
  20-teaching + 30-question-principles scoped to the new taxonomy
- UI: predictions render open with a Prediction eyebrow, verdict shows
  but the explanation tucks behind a toggle; the reading-thinking field
  mounts while a check waits (dictation claims it until reveal);
  answered card separates thinking vs thinking-while-reading blocks

components/reading-thinking.tsx

@@ -0,0 +1,77 @@
+"use client";
+
+import { useCallback } from "react";
+import { joinDictation, useDictationTarget } from "@/components/dictation";
+
+/**
+ * The reading-thinking field (owner design 2026-10-03, "two questions per
+ * teaching unit"): a quiet textarea for thinking WHILE READING the
+ * teaching prose — the same transfer channel the question dock's "Your
+ * thinking" gives the answer, opened one phase earlier. It mounts while a
+ * teach-phase check waits behind its reveal (the same cue that collapses
+ * the check), rides the check answer as the SEPARATE `readingThinking`
+ * channel (never conflated with the quiz thinking), and disappears with
+ * the question.
+ *
+ * Dictation: while the check sits UNREVEALED this field is the primary
+ * target (the dock releases its claim — dictated reading-thoughts land
+ * here, not in the hidden quiz field); once the learner reveals the
+ * check, the dock reclaims and this field is plain typing.
+ */
+export function ReadingThinkingField({
+	value,
+	onChange,
+	onEscape,
+	claim,
+}: {
+	value: string;
+	onChange: (v: string) => void;
+	/** Esc in the field stops dictation (threaded from the page's hook). */
+	onEscape?: () => void;
+	/** Primary dictation claim — true while the check is behind its reveal. */
+	claim: boolean;
+}) {
+	useDictationTarget(
+		useCallback(
+			(t: string) => {
+				onChange(joinDictation(value, t));
+			},
+			[value, onChange],
+		),
+		claim,
+	);
+	return (
+		<div
+			data-testid="reading-thinking-field"
+			className="pointer-events-auto mb-2 rounded-2xl border bg-card/60 px-3 py-2 transition-colors focus-within:border-primary/50"
+		>
+			<div className="pb-1 text-xs font-medium uppercase tracking-wide text-muted-foreground">
+				Thinking while reading
+			</div>
+			<textarea
+				value={value}
+				onChange={(e) => onChange(e.target.value)}
+				onKeyDown={(e) => {
+					if (e.key === "Escape") {
+						// Esc stops dictation (the strip's rule) — claimed so the
+						// window chain doesn't also read it as abort-turn.
+						e.preventDefault();
+						e.stopPropagation();
+						onEscape?.();
+						return;
+					}
+					// The dock's dumping convention: plain Enter is a newline.
+					// No submit button here — the check's own submit is this
+					// field's carrier — so ⌘↵ just blurs.
+					if (e.key === "Enter" && (e.metaKey || e.ctrlKey)) {
+						e.preventDefault();
+						e.currentTarget.blur();
+					}
+				}}
+				placeholder="What are you thinking as you read? Say as much as you like — it rides your next check answer to the teacher."
+				rows={1}
+				className="field-sizing-content lh-input max-h-40 w-full resize-none bg-transparent outline-none placeholder:text-muted-foreground/70"
+			/>
+		</div>
+	);
+}