fix(transit): keep the real silhouettes under sensor presets, make the selected trail visible, put Transit in Movement (#596)

## Changes

Follow-up to #587 after the owner's first look at the merged transit layer on Google 3D tiles.

- **Sensor presets keep the real silhouettes.** Under NVG, thermal (white-hot, black-hot, Ironbow) and noir, vehicles are the same silhouettes as in normal view, filled opaque white with a 2 px dark halo, at the CRT display sizes (26 px fleet, 39 px selected). The solid rounded "signature" bodies are gone.
- **The selected vehicle's trail is visible.** The retained history is now draped onto 3D tiles and terrain (`GroundPolylinePrimitive`, `ClassificationType.BOTH`, the way the traffic heat-lines are drawn), 3 px core over a 5 px dark backing, per-segment age colour, a short draped head clipped to the sprite. Two defects kept it off screen before: Cesium's per-instance attribute getters return copies, so the renderer's show/colour edits were discarded, and a marker did not recover after the camera jumped to it, which hid the trail with it. Trail geometry is now prepared on selection independent of floor resolution and marker visibility; sparse long intervals (rail) keep a bounded marker corridor instead of dropping the interval; classification survives map-source changes.
- **Transit sits in the Movement panel group** between Street Traffic and Bike Share (the panel orders by `PANEL_GROUPS`, not by catalog order; the catalog is moved too).

## How it was verified

- `npm run format:check` (854 files), `npm run check:boundaries`, `npm test` (4,062 passing), `npm run build` clean; tracking regression 109/109 in a real browser on Google 3D tiles.
- Browser harness (`scripts/qa-transit.mjs`), keyed on Google 3D tiles and keyless: keyed 194 pass, with the trail pixel check passing at 300, 600 and 900 m; the remaining keyed failures are the per-frame allocation gate already recorded as a follow-up from #587 (CPU and frame time within budget), four readability lines at threshold edges, and the card-anchor check now counting frames where the selected marker is legitimately off screen; keyless 193 pass with the remaining misses being threshold edges on the thin tram silhouette (centre 0.83–0.88 against 0.85) and one bus ring 0.28 against 0.25 on a pure-white roof.
- New harness checks: `Google 3D selected trail visible at 6 of 8 projected samples` (repeated off/on framebuffer captures at 300/600/900 m, samples outside the sprite footprint, a background-change negative control; fails on main, passes here), a camera-arrival check (select a moving vehicle, `setView` onto it, marker shown and trail body drawn within 2 s), `PANEL_ORDER` pinned, raster tests comparing every sensor raster's mask and aspect ratio to the normal silhouette.
- Direct look on a keyed build: a live CapMetro bus at 30 m/s selected through the layer API draws its draped trail along the highway lane (harness capture `keyed-600m-trail-visible.jpg`).
- Adversarial review by Codex Astra before the last two fix passes (stack-switch classification, marker corridor under the vertex cap, pixel-gate loophole), all three fixed with regressions.

Docs: `docs/CURRENT-STATE.md` and `CHANGELOG.md` updated in this PR. No data-source changes.

src/data/transitIcons.js

@@ -189,20 +189,21 @@ export function transitIcon(kind, px = FLEET_RASTER_PX, options = {}) {
   let uri = _iconCache.get(key);
   if (!uri) {
     const size = VIEW + 2 * frame.pad;
-    // Sensor signatures use a broad rounded envelope, without dark interior
-    // joints or a second outline eating into the hot core at display resolution.
-    const halfW = k === 'bus' || k === 'ferry' || k === 'unknown' ? 48 : 47;
-    const halfH = 48;
-    const radius = k === 'subway' ? 8 : k === 'rail' ? 12 : 14;
-    const capsule = `<path d="M${-halfW + radius},${-halfH} H${halfW - radius} Q${halfW},${-halfH} ${halfW},${-halfH + radius} V${halfH - radius} Q${halfW},${halfH} ${halfW - radius},${halfH} H${-halfW + radius} Q${-halfW},${halfH} ${-halfW},${halfH - radius} V${-halfH + radius} Q${-halfW},${-halfH} ${-halfW + radius},${-halfH} Z" fill="white" />`;
-    const body = profile === 'mono' ? capsule : BODIES[k];
+    // Reuse the exact outer path. Sensors fill its interior without panel ink.
+    const silhouette = BODIES[k].match(/<path d="([^"]+)"/)[1];
+    const body =
+      profile === 'mono'
+        ? `<path d="${silhouette}" fill="white" />`
+        : BODIES[k];
     const halo =
       frame.units > 0
-        ? body.replace(
-            /<path d="([^"]+)"\s+fill="white" [^/]*\/>/,
-            (_m, d) =>
-              `<path d="${d}" fill="none" stroke="${profile === 'mono' ? '#000000' : '#05080C'}" stroke-opacity="${profile === 'mono' ? 1 : 0.95}" stroke-width="${frame.units.toFixed(2)}" stroke-linejoin="round"/>`,
-          )
+        ? profile === 'mono'
+          ? `<path d="${silhouette}" fill="none" stroke="#05080C" stroke-opacity="1" stroke-width="${frame.units.toFixed(2)}" stroke-linejoin="round"/>`
+          : body.replace(
+              /<path d="([^"]+)"\s+fill="white" [^/]*\/>/,
+              (_m, d) =>
+                `<path d="${d}" fill="none" stroke="#05080C" stroke-opacity="0.95" stroke-width="${frame.units.toFixed(2)}" stroke-linejoin="round"/>`,
+            )
         : '';
     const svg =
       `<svg xmlns="http://www.w3.org/2000/svg" width="${Math.round(px * frame.ratio)}" height="${Math.round(px * frame.ratio)}" viewBox="${-frame.pad} ${-frame.pad} ${size} ${size}">` +