ui: consistency sweep — the 1ch rail geometry, Submit thinking, no auto-caps

Owner round 4 (2026-10-05):

- THE RAIL IS THE MISSING CHARACTER: rail + padding = exactly 1ch of
  the mono heading font. 'YOUR THINKING' (13ch) + rail == 'AGENT
  THINKING' (14ch) flush — the chevrons line up vertically, no fixed
  columns. The YOU heading joins the rail (label inside, like the
  thinking rows) — one quote geometry everywhere.
- HEADING REGISTER: YOUR THINKING / AGENT THINKING / YOU all use the
  card eyebrows' small mono caps (text-xs = the 11px rung, font-medium
  uppercase tracking-wide) — the app chrome is JetBrains Mono.
- SUBMIT THINKING: the practice button is now literally the question
  dock's Button (h-9, px-3.5) in one p-1 row with the hint left
  ('↵ submits · ⇧↵ newline') — the keyboard hints are back. Corner
  radii concentric in both docks: shell 16 − 6 = field 10 − 4 = button 6
  (rounded-[10px] fields, rounded-[6px] buttons — the old rounded-xl/12
  was the 'too large' culprit).
- MODEL NAMES: prettyModel no longer auto-capitalizes — names render
  exactly as their providers write them ('glm 5.3 flash').
- Quiz explanations pulled closer (mt-3 → mt-2).

tests/render-stats-bar.test.tsx

@@ -77,20 +77,20 @@ describe("stats bar", () => {
 		assert.match(html, /data-testid="stats-context">11k</);
 	});
 
-	it("prettyModel strips vendor + date suffix, capitalizes", () => {
-		assert.equal(prettyModel("z-ai/glm-5.3-flash"), "Glm 5.3 Flash");
-		assert.equal(prettyModel("qwen/qwen3.8-max-0902"), "Qwen3.8 Max");
+	it("prettyModel strips vendor + date suffix (no auto-caps)", () => {
+		assert.equal(prettyModel("z-ai/glm-5.3-flash"), "glm 5.3 flash"); // no auto-caps (owner round 4)
+		assert.equal(prettyModel("qwen/qwen3.8-max-0902"), "qwen3.8 max");
 	});
 
 	it("provider-qualified stamps (usage contract, model-slots wave)", () => {
 		// qualified: the provider rides as a quiet suffix — federation makes
 		// the same model via two providers different bookkeeping
-		assert.equal(prettyModel("openrouter:z-ai/glm-5.3-flash", true), "Glm 5.3 Flash · openrouter");
+		assert.equal(prettyModel("openrouter:z-ai/glm-5.3-flash", true), "glm 5.3 flash · openrouter");
 		assert.equal(prettyModel("openai:gpt-5.2", true), "Gpt 5.2 · openai");
 		// unqualified on a qualified stamp: provider silently dropped (old shape)
-		assert.equal(prettyModel("openrouter:z-ai/glm-5.3-flash"), "Glm 5.3 Flash");
+		assert.equal(prettyModel("openrouter:z-ai/glm-5.3-flash"), "glm 5.3 flash");
 		// qualified on a bare id: no suffix invented
-		assert.equal(prettyModel("z-ai/glm-5.3-flash", true), "Glm 5.3 Flash");
+		assert.equal(prettyModel("z-ai/glm-5.3-flash", true), "glm 5.3 flash");
 	});
 });