Merge lh-ui refinement wave (feat/ui-polish @ 8163437) into main

11 commits on fbeca36: minimal-color rounds 1-2 (phase color retired,
the braille spinner is the one working indicator; the chip is label-only),
typography rounds 1-5 (three-font rule enforced — CMU titles, Source Sans
session titles, JetBrains mono; snapped type ladder in globals.css with
the xxs rung merged into xs; lh-input caret at the font-metric floor;
session titles at prose size, message counts and active-row weight dropped,
ISO dates), header rounds 6/6b/6c/6d (60px top bar aligned to the sidebar
LH band; the open-sidebar toggle matches the close glyph at size-4 both
ways; SidebarToggle always-mounted with a lockstep animated slot — no more
one-frame title jump; title at text-3xl).

Semantic change folded in: `busy` in the chats list now means exactly "a
teach turn is in flight" — background jobs no longer spin the session row
(the sidebar's Background agents section is their channel).

Merge fallout fixed in the merge: components/graph-coverage.tsx (main's
coverage panel) held the last three text-xxs uses; with the rung deleted
they silently lost their size — mechanically swapped to text-xs, matching
lh-ui's own swap in graph-context-marker.tsx.

No file overlap with main's waves since fbeca36 (extraction coverage,
lh-graph merge, world-scale bake) — clean auto-merge. Gates: typecheck,
eslint, 496/496 tests, build. Live-verified on the dev server: 60px
header with 32px CMU title, label-only chip, snapped ladder active
(--lh-prose-size 16px, no --text-xxs rule anywhere), sidebar rows with
ISO dates, animated sidebar toggle with no header jump.

app/api/chats/route.ts

@@ -1,14 +1,17 @@
-import { createChat, isTurnRunning, listChats, listJobs, titleFromPrompt } from "@/src/server";
+import { createChat, isTurnRunning, listChats, titleFromPrompt } from "@/src/server";
 import type { ChatListItem } from "@/src/core";
 
 /** The session picker's list: record-derived summaries (phase, pending
- *  question) + live liveness — a running turn OR a background job marks
- *  the session busy (contracts.ts ChatListItem; the store can't see
- *  liveness, the route is the merge point). */
+ *  question) + live liveness — a running turn marks the session busy
+ *  (contracts.ts ChatListItem; the store can't see liveness, the route is
+ *  the merge point). Owner, minimal-color round: background jobs NO LONGER
+ *  count — the sidebar's Background agents section is their channel now
+ *  (a running spinner per row would double-signal them), so busy means
+ *  exactly "a teach turn is in flight". */
 export async function GET() {
 	const chats: ChatListItem[] = listChats().map((c) => ({
 		...c,
-		busy: isTurnRunning(c.id) || listJobs(c.id).some((j) => j.status === "running"),
+		busy: isTurnRunning(c.id),
 	}));
 	return Response.json({ chats });
 }