Explore: personal GPS heatmap tab under Athlete page

- bincio/explore.py: bake_tracks() simplifies GPS coords (RDP ε=0.0001),
  strips to [lng,lat], groups by sport type, writes per-handle tracks.json
- bake-tracks CLI command; render CLI calls _bake_tracks() after each build;
  strava_zip runs it once at end of batch
- /api/me/tracks endpoint serves the baked file; wipe_user cleans it up
- Explore.svelte: MapLibre full-screen map with sidebar — type pills,
  year/month date filter, Lines / Heatmap (global or by-type) view modes
- AthleteView: Explore tab visible only to profile owner (checks __bincioMe)
- Base.astro: fullscreen prop + Planner nav link

site/src/components/AthleteView.svelte

@@ -4,6 +4,7 @@
   import MmpChart from './MmpChart.svelte';
   import RecordsView from './RecordsView.svelte';
   import AthleteDrawer from './AthleteDrawer.svelte';
+  import Explore from './Explore.svelte';
   import { isUnlisted, formatElapsed, formatDistance, sportIcon } from '../lib/format';
   import { loadIndex, loadAthlete } from '../lib/dataloader';
 
@@ -21,9 +22,10 @@
   let error: string | null = null;
   let drawerOpen = false;
 
-  type Tab = 'power' | 'records' | 'segments' | 'profile';
+  type Tab = 'power' | 'records' | 'segments' | 'profile' | 'explore';
   let activeTab: Tab = 'power';
   let mounted = false;
+  let isOwner = false;
 
   interface SegmentSummaryItem {
     segment: { id: string; name: string; sport: string | null; distance_m: number };
@@ -80,9 +82,11 @@
   }
 
   onMount(async () => {
-    const TABS: Tab[] = ['power', 'records', 'segments', 'profile'];
+    isOwner = (window as any).__bincioMe === handle;
+    const TABS: Tab[] = ['power', 'records', 'segments', 'profile', 'explore'];
     const rawTab = new URLSearchParams(window.location.search).get('tab');
-    activeTab = TABS.includes(rawTab as Tab) ? (rawTab as Tab) : 'power';
+    const resolved = TABS.includes(rawTab as Tab) ? (rawTab as Tab) : 'power';
+    activeTab = (resolved === 'explore' && !isOwner) ? 'power' : resolved;
     mounted = true;
 
     // Resolve handle for the segments endpoint
@@ -140,12 +144,14 @@
     return hi >= 900 ? `${lo}+ bpm` : `${lo}–${hi} bpm`;
   }
 
-  const TABS: { key: Tab; label: string }[] = [
+  const ALL_TABS: { key: Tab; label: string; ownerOnly?: boolean }[] = [
     { key: 'power',    label: 'Power Curve' },
     { key: 'records',  label: 'Records'     },
     { key: 'segments', label: 'Segments'    },
     { key: 'profile',  label: 'Profile'     },
+    { key: 'explore',  label: 'Explore', ownerOnly: true },
   ];
+  $: TABS = ALL_TABS.filter(t => !t.ownerOnly || isOwner);
 </script>
 
 {#if loading}
@@ -325,6 +331,12 @@
       </div>
     {/if}
 
+  <!-- Explore tab -->
+  {:else if activeTab === 'explore'}
+    <div style="height: calc(100vh - 200px); margin: 0 -1rem -1.5rem;">
+      <Explore {handle} {base} embedded={true} />
+    </div>
+
   <!-- Profile tab -->
   {:else if activeTab === 'profile'}
     <div class="grid grid-cols-1 md:grid-cols-2 gap-4">