feat: max-speed marker scrubs timeline + timeline tick (FEAT-16)

- Clicking the amber max-speed map marker now jumps the replay to that point
- Add an amber tick on the scrubber at the max-speed position (clickable too)
- Both on Pi and server portal

static/yaris.css

@@ -334,6 +334,21 @@ body {
     padding-bottom: .375rem;
 }
 
+/* Max-speed tick overlaid on the trip replay scrubber. */
+.trip-max-tick {
+    position: absolute;
+    top: 50%;
+    transform: translate(-50%, -50%);
+    width: 12px;
+    height: 12px;
+    border-radius: 50%;
+    background: #f6c23e;
+    border: 2px solid #fff;
+    box-shadow: 0 0 0 1px rgba(0, 0, 0, .15);
+    cursor: pointer;
+    z-index: 2;
+}
+
 /* ── Dashcam / video ─────────────────────────────────────────────────────── */
 
 /* Desktop: truncate long filenames */