overlay_detail: add 'Refresh from Steam' button for workshop overlays

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

l4d2web/templates/overlay_detail.html

@@ -51,6 +51,10 @@
     <label>Workshop input <textarea name="input" rows="3" placeholder="123456789&#10;https://steamcommunity.com/sharedfiles/filedetails/?id=987654321"></textarea></label>
     <button type="submit">Add</button>
   </form>
+  <form method="post" action="/overlays/{{ overlay.id }}/refresh" class="stack workshop-refresh-form">
+    <input type="hidden" name="csrf_token" value="{{ session.get('csrf_token', '') }}">
+    <button type="submit">Refresh from Steam</button>
+  </form>
   {% endif %}
 
   <div id="overlay-item-table">

l4d2web/tests/test_pages.py

@@ -742,3 +742,32 @@ def test_overlay_detail_no_global_source_block(auth_client_with_server) -> None:
 
     assert "Global source" not in text
     assert "source_url" not in text
+
+
+def test_workshop_overlay_detail_renders_refresh_button(auth_client_with_server) -> None:
+    """The owner sees a 'Refresh from Steam' button on their workshop overlay."""
+    with session_scope() as s:
+        user_id = s.query(User).filter_by(username="alice").one().id
+    overlay_id = _seed_overlay("ws-refresh-button", "workshop", user_id)
+
+    response = auth_client_with_server.get(f"/overlays/{overlay_id}")
+    text = response.get_data(as_text=True)
+
+    assert response.status_code == 200
+    assert "Refresh from Steam" in text
+    assert f'action="/overlays/{overlay_id}/refresh"' in text
+
+
+def test_workshop_overlay_refresh_button_hidden_during_build(auth_client_with_server) -> None:
+    """While a build is in flight the Refresh button hides, matching the Add form."""
+    with session_scope() as s:
+        user_id = s.query(User).filter_by(username="alice").one().id
+    overlay_id = _seed_overlay("ws-refresh-hidden", "workshop", user_id)
+    with session_scope() as s:
+        s.add(Job(user_id=user_id, overlay_id=overlay_id, operation="build_overlay", state="running"))
+
+    response = auth_client_with_server.get(f"/overlays/{overlay_id}")
+    text = response.get_data(as_text=True)
+
+    assert response.status_code == 200
+    assert "Refresh from Steam" not in text