feat(hikes): forgiving map selection, photo lightbox, detail polish

Map interaction:
- Overview map: widen the canvas renderer hit-test (tolerance) so a route
  can be hovered/clicked from a comfortable margin instead of demanding a
  pixel-perfect click on the thin line.
- Detail map: drive the elevation cursor from a whole-map mousemove that
  snaps to the nearest track point within ~70 px (track cached in
  layer-point space, refreshed on zoom/move), instead of requiring the
  pointer to ride exactly on the trail. The hover pin now renders for
  map-sourced hovers too, and is recoloured to nord red as a distinct
  "you are here" marker. Trail polyline made non-interactive.

Detail page:
- Move the photo strip above the stats row and trim it (3:2 cards).
- Add a fullscreen lightbox: an expand button on each card opens the
  full-res image with prev/next, arrow keys, Esc, backdrop-close and a
  body-scroll lock; opening/stepping syncs the map + strip. The card's
  existing click (map-position sync) is preserved.
- Cap inline prose images at 680 px (centered) so they don't blow up to
  full width in the single-column layout on wider screens; the desktop
  two-column layout is unaffected.

src/routes/hikes/[slug]/+page.svelte

@@ -372,6 +372,12 @@
 		</div>
 	</section>
 
+	{#if track && track.length > 0 && visibleImagePoints.length > 0}
+		<section class="strip-area">
+			<HikePhotoStrip images={visibleImagePoints} {track} />
+		</section>
+	{/if}
+
 	<section class="metrics" aria-label="Tourendaten">
 		{#if hike.icon}
 			<img class="route-icon" src={hike.icon} alt="" aria-hidden="true" />
@@ -445,12 +451,6 @@
 		</section>
 	{/if}
 
-	{#if track && track.length > 0 && visibleImagePoints.length > 0}
-		<section class="strip-area">
-			<HikePhotoStrip images={visibleImagePoints} {track} />
-		</section>
-	{/if}
-
 	<section class="scroll-area">
 		<aside class="trail-col">
 			{#if track && track.length > 0}