Add map view toggle to activity feed

Adds a List/Map toggle to the feed and @user profile pages. The map view
plots all filtered activities as sport-coloured tracks on a MapLibre map
with no extra requests (uses preview_coords already in memory). Clicking
a track or list row selects it: pans the map to fit, expands the list
item with key stats, and scrolls it into view.

site/src/components/ActivityFeed.svelte

@@ -3,6 +3,7 @@
   import type { ActivitySummary, BASIndex, Sport } from '../lib/types';
   import { formatDistance, formatDuration, formatElevation, formatDate, isUnlisted, sportIcon, sportColor, sportLabel } from '../lib/format';
   import { loadIndexPaged, loadShardActivities, loadCombinedFeed } from '../lib/dataloader';
+  import FeedMapView from './FeedMapView.svelte';
 
   /** Render preview_coords as an SVG polyline path string. */
   function trackPath(coords: [number, number][] | null, w: number, h: number): string {
@@ -50,6 +51,7 @@
   let loading = true;
   let loadingMore = false;
   let error = '';
+  let viewMode: 'list' | 'map' = 'list';
   let mounted = false;
   let pendingShards: string[] = [];
   /** Grand total from feed.json — shows instance-wide count even before all pages are loaded. */
@@ -247,7 +249,7 @@
     bind:value={query}
     class="flex-1 px-4 py-2 rounded-lg bg-zinc-900 border border-zinc-700 text-white placeholder-zinc-500 text-sm focus:outline-none focus:border-zinc-500 transition-colors"
   />
-  <div class="flex gap-2">
+  <div class="flex gap-2 items-center">
     <div class="flex items-center gap-1.5 px-3 py-2 rounded-lg bg-zinc-900 border border-zinc-700 focus-within:border-zinc-500 transition-colors">
       <span class="text-xs text-zinc-500 whitespace-nowrap select-none">From</span>
       <input
@@ -269,6 +271,22 @@
         class="bg-transparent text-white text-sm focus:outline-none [color-scheme:dark]"
       />
     </div>
+    <div class="flex rounded-lg border border-zinc-700 overflow-hidden text-sm shrink-0">
+      <button
+        class="px-3 py-2 transition-colors"
+        class:bg-zinc-800={viewMode === 'list'}
+        class:text-white={viewMode === 'list'}
+        class:text-zinc-400={viewMode !== 'list'}
+        on:click={() => viewMode = 'list'}
+      >List</button>
+      <button
+        class="px-3 py-2 border-l border-zinc-700 transition-colors"
+        class:bg-zinc-800={viewMode === 'map'}
+        class:text-white={viewMode === 'map'}
+        class:text-zinc-400={viewMode !== 'map'}
+        on:click={() => viewMode = 'map'}
+      >Map</button>
+    </div>
   </div>
 </div>
 
@@ -324,6 +342,25 @@
   </div>
 {:else if error}
   <p class="text-red-400 text-center py-12">Could not load activities: {error}</p>
+{:else if viewMode === 'map'}
+  <FeedMapView activities={withSearch} base={base} />
+  {#if hasMore}
+    <div class="text-center mt-4">
+      <button
+        class="px-6 py-2 rounded-full border border-zinc-700 text-zinc-300 hover:border-zinc-500 hover:text-white disabled:opacity-40 transition-colors text-sm"
+        disabled={loadingMore}
+        on:click={loadMore}
+      >
+        {#if loadingMore}
+          Loading…
+        {:else if canShowMore}
+          Load more ({filtered.length - shown} remaining)
+        {:else}
+          Load older activities ({pendingShards.length} more {pendingShards.length === 1 ? 'period' : 'periods'})
+        {/if}
+      </button>
+    </div>
+  {/if}
 {:else if withSearch.length === 0}
   <p class="text-zinc-500 text-center py-12">
     {#if loadingAllShards}Loading…{:else if query.trim()}No activities match "{query.trim()}".{:else}No activities found.{/if}

site/src/components/FeedMapView.svelte

@@ -0,0 +1,190 @@
+<script lang="ts">
+  import { onMount, onDestroy, tick } from 'svelte';
+  import maplibregl from 'maplibre-gl';
+  import 'maplibre-gl/dist/maplibre-gl.css';
+  import type { ActivitySummary } from '../lib/types';
+  import { formatDistance, formatDuration, formatElevation, formatDate, sportIcon, sportColor } from '../lib/format';
+
+  export let activities: ActivitySummary[] = [];
+  export let base: string = '/';
+
+  let mapEl: HTMLDivElement;
+  let map: any;
+  let sourceReady = false;
+  let selectedId: string | null = null;
+
+  const TILE_STYLE = 'https://tiles.openfreemap.org/styles/positron';
+
+  function bboxFromCoords(coords: [number, number][]): [[number, number], [number, number]] {
+    const lons = coords.map(([, lon]) => lon);
+    const lats = coords.map(([lat]) => lat);
+    return [[Math.min(...lons), Math.min(...lats)], [Math.max(...lons), Math.max(...lats)]];
+  }
+
+  function toGeoJSON(acts: ActivitySummary[]) {
+    return {
+      type: 'FeatureCollection' as const,
+      features: acts
+        .filter(a => a.preview_coords?.length)
+        .map(a => ({
+          type: 'Feature' as const,
+          geometry: {
+            type: 'LineString' as const,
+            coordinates: a.preview_coords!.map(([lat, lon]) => [lon, lat]),
+          },
+          properties: { id: a.id, color: sportColor(a.sport) },
+        })),
+    };
+  }
+
+  // Update GeoJSON source whenever activities or sourceReady changes
+  $: if (sourceReady && activities) {
+    (map?.getSource('activities') as any)?.setData(toGeoJSON(activities));
+  }
+
+  // Update paint whenever selectedId changes (after map layers exist)
+  $: if (map?.getLayer('act-line')) {
+    const sel = selectedId ?? '';
+    map.setPaintProperty('act-line', 'line-width',
+      ['case', ['==', ['get', 'id'], sel], 4, 2]);
+    map.setPaintProperty('act-line', 'line-opacity',
+      ['case', ['==', ['get', 'id'], sel], 1.0, 0.55]);
+  }
+
+  async function selectActivity(id: string) {
+    selectedId = selectedId === id ? null : id;
+    if (!selectedId) return;
+    const act = activities.find(a => a.id === selectedId);
+    if (act?.preview_coords?.length && map) {
+      map.fitBounds(bboxFromCoords(act.preview_coords), { padding: 60, maxZoom: 15, duration: 500 });
+    }
+    await tick();
+    document.getElementById(`fmv-${selectedId}`)?.scrollIntoView({ behavior: 'smooth', block: 'nearest' });
+  }
+
+  onMount(() => {
+    map = new maplibregl.Map({
+      container: mapEl,
+      style: TILE_STYLE,
+      center: [0, 30],
+      zoom: 2,
+      attributionControl: false,
+    });
+    map.addControl(new maplibregl.NavigationControl({ showCompass: false }), 'top-right');
+    map.addControl(new maplibregl.AttributionControl({ compact: true }), 'bottom-right');
+
+    map.on('load', () => {
+      map.addSource('activities', {
+        type: 'geojson',
+        data: { type: 'FeatureCollection', features: [] },
+      });
+
+      // Wide transparent hit area for easier clicking
+      map.addLayer({ id: 'act-hit', type: 'line', source: 'activities',
+        paint: { 'line-color': 'transparent', 'line-width': 14 } });
+
+      map.addLayer({ id: 'act-line', type: 'line', source: 'activities',
+        layout: { 'line-cap': 'round', 'line-join': 'round' },
+        paint: {
+          'line-color': ['get', 'color'],
+          'line-width': 2,
+          'line-opacity': 0.55,
+        },
+      });
+
+      map.on('click', 'act-hit', (e: any) => {
+        const id = e.features?.[0]?.properties?.id;
+        if (id) selectActivity(id);
+      });
+      map.on('mouseenter', 'act-hit', () => { map.getCanvas().style.cursor = 'pointer'; });
+      map.on('mouseleave', 'act-hit', () => { map.getCanvas().style.cursor = ''; });
+
+      sourceReady = true;
+
+      // Fit to all loaded tracks on initial render
+      const geo = toGeoJSON(activities);
+      if (geo.features.length > 0) {
+        const allCoords = geo.features.flatMap(f => (f.geometry as any).coordinates as [number, number][]);
+        const lons = allCoords.map(c => c[0]);
+        const lats = allCoords.map(c => c[1]);
+        map.fitBounds(
+          [[Math.min(...lons), Math.min(...lats)], [Math.max(...lons), Math.max(...lats)]],
+          { padding: 40, maxZoom: 14, duration: 0 }
+        );
+      }
+    });
+  });
+
+  onDestroy(() => { map?.remove(); });
+</script>
+
+<div class="rounded-xl border border-zinc-800 overflow-hidden">
+  <!-- Map -->
+  <div style="height: 420px;" class="relative">
+    <div bind:this={mapEl} class="w-full h-full"></div>
+  </div>
+
+  <!-- Activity list -->
+  <div class="border-t border-zinc-800 max-h-[360px] overflow-y-auto">
+    {#if activities.length === 0}
+      <p class="text-zinc-500 text-sm text-center py-8">No activities to display.</p>
+    {:else}
+      <div class="divide-y divide-zinc-800/60">
+        {#each activities as a (a.id)}
+          <div
+            id="fmv-{a.id}"
+            class="px-4 py-3 cursor-pointer transition-colors hover:bg-zinc-800/40"
+            class:bg-zinc-800={selectedId === a.id}
+            on:click={() => selectActivity(a.id)}
+            role="button"
+            tabindex="0"
+            on:keydown={e => e.key === 'Enter' && selectActivity(a.id)}
+          >
+            <!-- Summary row -->
+            <div class="flex items-center justify-between gap-3">
+              <div class="flex items-center gap-2 min-w-0">
+                <span class="shrink-0 text-base">{sportIcon(a.sport)}</span>
+                <div class="min-w-0">
+                  <a
+                    href={a.detail_url ? `${base}activity/${a.id}/` : `${base}activity/local/?id=${a.id}`}
+                    class="text-sm font-medium text-white hover:text-[--accent] transition-colors truncate block"
+                    on:click|stopPropagation
+                  >{a.title}</a>
+                  <p class="text-xs text-zinc-500">
+                    {formatDate(a.started_at)}{#if a.handle} · @{a.handle}{/if}
+                  </p>
+                </div>
+              </div>
+              <div class="flex gap-3 text-xs shrink-0">
+                {#if a.distance_m != null}
+                  <span class="text-white">{formatDistance(a.distance_m)}</span>
+                {/if}
+                {#if a.elevation_gain_m != null}
+                  <span class="text-zinc-400">↑{formatElevation(a.elevation_gain_m)}</span>
+                {/if}
+              </div>
+            </div>
+
+            <!-- Expanded stats when selected -->
+            {#if selectedId === a.id}
+              <div class="mt-2.5 pl-8 grid grid-cols-2 sm:grid-cols-4 gap-x-6 gap-y-1 text-xs">
+                {#if a.moving_time_s != null}
+                  <div><span class="text-white font-medium">{formatDuration(a.moving_time_s)}</span> <span class="text-zinc-500">time</span></div>
+                {/if}
+                {#if a.avg_speed_kmh != null}
+                  <div><span class="text-white font-medium">{a.avg_speed_kmh.toFixed(1)} km/h</span> <span class="text-zinc-500">avg speed</span></div>
+                {/if}
+                {#if a.avg_hr_bpm != null}
+                  <div><span class="text-white font-medium">{a.avg_hr_bpm} bpm</span> <span class="text-zinc-500">avg HR</span></div>
+                {/if}
+                {#if a.avg_power_w != null}
+                  <div><span class="text-white font-medium">{a.avg_power_w} W</span> <span class="text-zinc-500">avg power</span></div>
+                {/if}
+              </div>
+            {/if}
+          </div>
+        {/each}
+      </div>
+    {/if}
+  </div>
+</div>