ui: round 5 — AGENT'S THINKING buys the 3ch rail; the standard chord; dashed model names

- THE 3CH RAIL: 'AGENT’S THINKING' (16ch, flush) − 'YOUR THINKING' (13ch)
  = 3ch of mono — the rail widens to 3ch (border + padding), keeping the
  chevrons aligned while giving the quote room to breathe (the 1ch rail
  read cramped). YOU row follows.
- THE STANDARD CHORD everywhere: Enter submits, Shift+Enter is a
  newline, ⌘/Ctrl+Enter works too — the teaching thinking field drops
  the ⌘-only Gmail convention; the hint reads '↵ submits · ⇧↵ newline'
  in both docks, shown in text mode too (it Enter-submits as well).
- The transcript-end optimistic placeholder joins the register: small
  mono caps THINKING… (was text-sm sentence case).
- Model names keep their dashes: prettyModel renders 'glm-5.3-flash'
  exactly as written (no auto-caps, no dash→space join).

components/thinking-block.tsx

@@ -33,16 +33,18 @@ export function ThinkingBlock({
 	return (
 		/* The rail GROUPS and the rail IS THE MISSING CHARACTER (owner
 		   rounds, 2026-10-05): the heading sits INSIDE the rail, and the
-		   rail's full width (border + padding) is exactly ONE CHARACTER of
-		   the mono heading font — 'YOUR THINKING' is one char shorter than
-		   'AGENT THINKING', so with the user row offset by the rail and the
-		   agent row flush, the chevrons line up vertically. The heading
+		   rail's full width (border + padding) is exactly THREE CHARACTERS of
+		   the mono heading font — 'YOUR THINKING' is three chars shorter
+		   than 'AGENT'S THINKING', so with the user row offset by the rail
+		   and the agent row flush, the chevrons line up vertically. Three
+		   (not one, owner round 5): the wider gap reads better than the
+		   cramped single-char rail. The heading
 		   register is the card eyebrows' small mono caps (text-xs = the
 		   11px rung). */
 		<div
 			data-testid={testId}
 			data-commit={dataCommit === undefined ? undefined : dataCommit ? "true" : "false"}
-			className="lh-card-enter my-1 w-full border-l-2 border-muted-foreground/30 pl-[calc(1ch-2px)] font-ui text-xs"
+			className="lh-card-enter my-1 w-full border-l-2 border-muted-foreground/30 pl-[calc(3ch-2px)] font-ui text-xs"
 		>
 			<button
 				type="button"