feat(roadtrip): bring the road trip addon to the phone

A road trip tab on the mobile trip screen: the stage as a chain, the same
map underneath it, the sheets a passenger needs, and a search along the
route.

The addon was desktop only because road trip MODE is a data switch rather
than a view switch. It rewrites `assignments` and `places` for the whole
planner hook, and every mobile sheet is permanently mounted and reads those
same two lists, so turning it on there brought back documented regressions.
The mode flag is therefore untouched. A second flag, `roadtripFeedActive`,
feeds only the routing round and does it off the STORED assignments, so the
phone gets the drive without what the mode drags along with it.

The map is one instance shared by the plan tab and the road trip tab,
hoisted into a single JSX expression so React keeps it in the same position
and the WebGL context is never torn down on a tab switch.

The corridor search is scoped to what a phone can afford: a window of the
day rather than all of it, a smaller tile ceiling, a capped retry pass and a
deadline. The standard search is three requests where the desk makes
fifteen. The categories are deliberately not narrowed, because they all ride
one query per box, so a second one costs nothing.

Two gaps found while wiring it up are closed here as well. The fuel search
drew its offers nowhere on the phone, so the button did nothing visible;
they are in the dry band now, with the detour, the spare range and an accept
button. And the map credit opened as a two line ribbon across a screen the
map fills: both GL engines now start it collapsed, and Leaflet, which has no
collapsed mode of its own, is given one.

client/src/components/Map/MapViewGL.tsx

@@ -1170,6 +1170,23 @@ export function MapViewGL({
       maxWidth: '240px',
       className: 'trek-map-popup',
     })
+    /*
+     * The credit starts as the little (i), not as a ribbon across the map.
+     *
+     * Both engines collapse their attribution below 640px, and both then open it
+     * anyway and wait for a drag before tucking it away. On a phone, where the map IS
+     * the screen, that means the first thing anybody sees is a two-line grey band
+     * over the bottom of it. Dragging is exactly what maplibre does on its own
+     * `drag` handler; this only starts where that would have ended up, so the credit
+     * is one tap away and nothing about it is removed.
+     */
+    map.once('idle', () => {
+      const attrib = containerRef.current?.querySelector('.maplibregl-ctrl-attrib.maplibregl-compact-show')
+        ?? containerRef.current?.querySelector('.mapboxgl-ctrl-attrib.mapboxgl-compact-show')
+      attrib?.classList.remove('maplibregl-compact-show', 'mapboxgl-compact-show')
+      attrib?.removeAttribute('open')
+    })
+
     // Hand the map out so the trip planner can render its own compass pill next to
     // the POI pill (a custom round control instead of Mapbox's default top-right one).
     onMapReadyRef.current?.(map)