status: consolidate the pill to one dot + one word; upgrade the panel

- pill: two host dots -> ONE consolidated state (down > slow > up) —
  the at-a-glance question is 'can I watch?', which is one state;
  per-host detail belongs in the tap panel
- panel: dashed slow-threshold line in the CDN sparkline (drawn at the
  server's real threshold, not a client copy) + origin up/down step
  sparkline so 'how long has the origin been down' is visible
- server: origin probe keeps a 20-sample hist like the CDN probe;
  DEGRADED threshold is now ANIWEB_CDN_KBPS (default 40) and is
  returned in /api/cdn so the UI draws the line at the live value
- tests: pill assertions switched to consolidated states; fixtures
  carry origin hist + threshold; assert both sparklines + threshold line
- docs: README + SPEC synced; preview on :8322 restarted (pid 44382)

static/style.css

@@ -176,12 +176,14 @@ header .pill { display: flex; align-items: center; gap: .4rem; flex: none;
 .sp-row { font-variant-numeric: tabular-nums; }
 .sp-cap { color: var(--muted); font-size: .68rem; }
 .sp-svg { width: 100%; height: 28px; color: var(--acc); }
+.sp-svg.bad { color: #ef4444; }  /* origin currently down */
 .sp-svg polyline { fill: none; stroke: currentColor; stroke-width: 1.5; }
-header .pill i { width: 8px; height: 8px; flex: none; border-radius: 50%; background: #6b7280; }
-header .pill .o.ok, header .pill .c.ok { background: #22c55e; }
-header .pill .c.degraded { background: #f59e0b; }
-header .pill .o.down { background: #ef4444; }
-header .pill.odown { border-color: #7f1d1d; }
+.sp-thr { stroke: #f59e0b; stroke-width: 1; stroke-dasharray: 3 3; }
+header .pill .d { width: 8px; height: 8px; flex: none; border-radius: 50%; background: #6b7280; }
+header .pill .d.ok { background: #22c55e; }
+header .pill .d.slow { background: #f59e0b; }
+header .pill .d.down { background: #ef4444; }
+header .pill.down { border-color: #7f1d1d; }
 #toasts { position: fixed; bottom: 1rem; left: 50%; transform: translateX(-50%);
   display: flex; flex-direction: column; gap: .4rem; z-index: 9; }
 @keyframes toast-in { from { opacity: 0; transform: translateY(.4rem); } }