ui: the document look — one language for every thinking, no bubbles

Owner round 2 (2026-10-05), Slice F:

- USER TEXT: the right-aligned bubble is gone. User messages are
  full-width document rows — muted 'You' label, muted quote rail,
  full-opacity text. Learner words are content, not a chat-app tell.
- USER THINKING (everywhere): arrives COLLAPSED as a trigger row in the
  exact register of the agent's reasoning rows (muted label + chevron +
  hover affordance); expanding opens the quote block — rail, 50%
  opacity, italics. The inner-voice signature. The ThinkingBlock loses
  its shell/border: pure document material.
- QUIZ CARDS: the answer's thinking is the SAME collapsible row, same
  placement, just inside the container; the explanation drops to 50%
  opacity (upright — italics stays the thinking signature).
- AGENT'S THINKING: the duration bookkeeping is gone (it was live-turn
  state that died to 'a few seconds' on remount anyway) — the settled
  row reads static 'Agent's thinking', pairing with 'Your thinking'.
  Spinner + shimmer stay the working signal while streaming.
- Glance law: user thinking = rail + 50% italic; agent thinking = no
  rail; user text = upright, full opacity, 'You' label.

app/globals.css

@@ -286,7 +286,7 @@ body {
 }
 
 .dock-variant {
-	animation: dock-variant-in 160ms cubic-bezier(0.2, 0.8, 0.2, 1);
+	animation: dock-variant-in 120ms cubic-bezier(0.2, 0.8, 0.2, 1);
 }
 
 /* ============================================================
@@ -548,7 +548,7 @@ body {
 }
 
 .lh-card-enter {
-	animation: lh-card-enter 150ms ease-out;
+	animation: lh-card-enter 120ms ease-out;
 }
 
 @media (prefers-reduced-motion: reduce) {