feat: export gear maintenance log as CSV

site/src/components/AthleteView.svelte

@@ -83,6 +83,41 @@
 
   const GEAR_ICONS: Record<string, string> = { bike: '🚲', shoes: '👟', skis: '🎿', other: '⚙️' };
 
+  function exportGearCsv() {
+    const esc = (v: unknown) => `"${String(v ?? '').replace(/"/g, '""')}"`;
+    const rows: string[] = [
+      ['gear_name', 'gear_type', 'gear_distance_km', 'part_name', 'part_threshold_km',
+       'part_distance_since_last_km', 'replacement_date', 'replacement_note'].join(',')
+    ];
+    for (const item of gearItems) {
+      const gearKm = ((gearDistances[item.name] ?? 0) / 1000).toFixed(1);
+      const parts = item.parts ?? [];
+      if (parts.length === 0) {
+        rows.push([esc(item.name), esc(item.type), gearKm, '', '', '', '', ''].join(','));
+        continue;
+      }
+      for (const part of parts) {
+        const partKm = partDistanceKm(item.name, part).toFixed(1);
+        const reps = part.replacements.slice().reverse();
+        if (reps.length === 0) {
+          rows.push([esc(item.name), esc(item.type), gearKm, esc(part.name),
+            part.threshold_km ?? '', partKm, '', ''].join(','));
+        } else {
+          for (const rep of reps) {
+            rows.push([esc(item.name), esc(item.type), gearKm, esc(part.name),
+              part.threshold_km ?? '', partKm, rep.date, esc(rep.note ?? '')].join(','));
+          }
+        }
+      }
+    }
+    const blob = new Blob([rows.join('\n')], { type: 'text/csv' });
+    const a = document.createElement('a');
+    a.href = URL.createObjectURL(blob);
+    a.download = 'gear.csv';
+    a.click();
+    URL.revokeObjectURL(a.href);
+  }
+
   function fmtDate(iso: string): string {
     const [y, m, d] = iso.split('-');
     return `${d}/${m}/${y}`;
@@ -847,6 +882,12 @@
             disabled={gearAdding || !gearAddName.trim()}
             class="text-xs px-3 py-1.5 rounded-lg border border-zinc-700 hover:border-zinc-500 text-zinc-400 hover:text-white transition-colors disabled:opacity-40"
           >{gearAdding ? 'Adding…' : '+ Add gear'}</button>
+          {#if gearItems.length > 0}
+            <button
+              on:click={exportGearCsv}
+              class="text-xs px-3 py-1.5 rounded-lg border border-zinc-700 hover:border-zinc-500 text-zinc-400 hover:text-white transition-colors ml-auto"
+            >Export CSV</button>
+          {/if}
         </div>
       {/if}
     </div>