F14: add per-activity delete (DELETE /api/activity/{id} + drawer button)

Server endpoint removes the activity JSON, GeoJSON, timeseries, sidecar
edit, and images directory. Also purges the dedup cache entry so the
file can be re-uploaded if needed. Runs merge_all + rebuild afterwards.

EditDrawer: two-click delete button (click once → "Confirm delete?",
click again → deletes). On success, dispatches 'deleted' event.
ActivityDetail navigates back to the feed on delete.

bincio/serve/server.py

@@ -597,6 +597,56 @@ async def post_activity(
     return JSONResponse({"ok": True})
 
 
+@app.delete("/api/activity/{activity_id}")
+async def delete_activity(
+    activity_id: str,
+    bincio_session: Optional[str] = Cookie(default=None),
+) -> JSONResponse:
+    """Delete a single activity and all associated files for the logged-in user."""
+    user = _require_user(bincio_session)
+    _check_id(activity_id)
+    dd = _get_data_dir() / user.handle
+    acts_dir = dd / "activities"
+
+    json_path = acts_dir / f"{activity_id}.json"
+    if not json_path.exists():
+        raise HTTPException(404, "Activity not found")
+
+    import shutil
+
+    # Remove the source files (activities dir)
+    for suffix in (".json", ".geojson", ".timeseries.json"):
+        p = acts_dir / f"{activity_id}{suffix}"
+        p.unlink(missing_ok=True)
+
+    # Remove sidecar edit and images
+    sidecar = dd / "edits" / f"{activity_id}.md"
+    sidecar.unlink(missing_ok=True)
+    images_dir = dd / "edits" / "images" / activity_id
+    if images_dir.exists():
+        shutil.rmtree(images_dir)
+
+    # Remove from dedup cache so the file can be re-uploaded if needed
+    cache_path = dd / ".bincio_cache.json"
+    if cache_path.exists():
+        try:
+            cache = json.loads(cache_path.read_text(encoding="utf-8"))
+            if isinstance(cache, dict) and "activities" in cache:
+                cache["activities"] = [
+                    a for a in cache["activities"] if a.get("id") != activity_id
+                ]
+                cache_path.write_text(json.dumps(cache, indent=2, ensure_ascii=False))
+        except Exception:
+            pass  # corrupt cache — leave it; next extract will rebuild
+
+    # Full merge needed: activity removed from index
+    from bincio.render.merge import merge_all
+    merge_all(dd)
+    _trigger_rebuild(user.handle)
+
+    return JSONResponse({"ok": True})
+
+
 @app.get("/api/activity/{activity_id}/images")
 async def list_images(
     activity_id: str,

site/src/components/ActivityDetail.svelte

@@ -112,7 +112,7 @@
 <svelte:window on:keydown={onKeydown} />
 
 {#if editOpen && editEnabled}
-  <EditDrawer activityId={activity.id} {editUrl} on:saved={onSaved} on:close={() => editOpen = false} />
+  <EditDrawer activityId={activity.id} {editUrl} on:saved={onSaved} on:close={() => editOpen = false} on:deleted={() => { window.location.href = base; }} />
 {/if}
 
 <!-- Lightbox -->

site/src/components/EditDrawer.svelte

@@ -5,7 +5,7 @@
   export let activityId: string;
   export let editUrl: string;
 
-  const dispatch = createEventDispatcher<{ saved: { title: string; description: string }; close: void }>();
+  const dispatch = createEventDispatcher<{ saved: { title: string; description: string }; close: void; deleted: void }>();
 
   const SPORTS: Sport[] = ['cycling', 'running', 'hiking', 'walking', 'swimming', 'skiing', 'other'];
   const STAT_PANELS = [
@@ -21,6 +21,8 @@
   let saving = false;
   let saveStatus = '';
   let saveOk = false;
+  let confirmDelete = false;
+  let deleting = false;
 
   // Form state
   let title = '';
@@ -120,6 +122,22 @@
       : [...hideStats, key];
   }
 
+  async function deleteActivity() {
+    if (!confirmDelete) { confirmDelete = true; return; }
+    deleting = true;
+    try {
+      const res = await fetch(api, { method: 'DELETE' });
+      if (!res.ok) throw new Error(await res.text());
+      dispatch('deleted');
+    } catch (e: any) {
+      saveStatus = `Delete failed: ${e.message}`;
+      saveOk = false;
+      confirmDelete = false;
+    } finally {
+      deleting = false;
+    }
+  }
+
   load();
 </script>
 
@@ -284,11 +302,26 @@
     <div class="px-5 py-4 border-t border-zinc-800 flex items-center gap-3 shrink-0">
       <button
         class="px-4 py-2 bg-blue-600 hover:bg-blue-500 disabled:opacity-40 text-white text-sm font-medium rounded-lg transition-colors"
-        disabled={saving}
+        disabled={saving || deleting}
         on:click={save}
       >
         {saving ? 'Saving…' : 'Save'}
       </button>
+      <button
+        class="px-3 py-2 text-sm font-medium rounded-lg border transition-colors disabled:opacity-40 ml-auto"
+        class:border-zinc-700={!confirmDelete}
+        class:text-zinc-500={!confirmDelete}
+        class:hover:border-red-600={!confirmDelete}
+        class:hover:text-red-400={!confirmDelete}
+        class:border-red-500={confirmDelete}
+        class:text-red-400={confirmDelete}
+        class:bg-red-950={confirmDelete}
+        disabled={deleting}
+        on:click={deleteActivity}
+        on:blur={() => confirmDelete = false}
+      >
+        {deleting ? 'Deleting…' : confirmDelete ? 'Confirm delete?' : 'Delete'}
+      </button>
       {#if saveStatus}
         <span class="text-xs" class:text-green-400={saveOk} class:text-red-400={!saveOk}>
           {saveStatus}