feat(session): reset running session start time to now from list

Adds a confirm-gated button on running sessions in the session list that
sets timestamp_start to now (issue #33). The htmx path returns HX-Refresh;
ButtonGroup gains optional hx_confirm/hx_swap keys.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

games/templates/icons/reset.html

@@ -0,0 +1,11 @@
+<svg xmlns="http://www.w3.org/2000/svg"
+     viewBox="0 0 24 24"
+     fill="none"
+     stroke="currentColor"
+     stroke-width="2"
+     stroke-linecap="round"
+     stroke-linejoin="round"
+     class="text-black dark:text-white w-4 h-4">
+    <path d="M3 12a9 9 0 1 0 3-6.7L3 8" />
+    <path d="M3 3v5h5" />
+</svg>

games/urls.py

@@ -147,6 +147,11 @@ urlpatterns = [
         session.end_session,
         name="list_sessions_end_session",
     ),
+    path(
+        "session/start/reset-to-now/from-list/<int:session_id>",
+        session.reset_session_start,
+        name="list_sessions_reset_session_start",
+    ),
     path("session/list", session.list_sessions, name="list_sessions"),
     path("session/search", session.search_sessions, name="search_sessions"),
     path(

games/views/session.py

@@ -144,6 +144,24 @@ def list_sessions(request: HttpRequest, search_string: str = "") -> HttpResponse
                             }
                             if session.timestamp_end is None
                             else {},
+                            {
+                                "href": reverse(
+                                    "games:list_sessions_reset_session_start",
+                                    args=[session.pk],
+                                ),
+                                "hx_get": reverse(
+                                    "games:list_sessions_reset_session_start",
+                                    args=[session.pk],
+                                ),
+                                "hx_confirm": (
+                                    "Reset this session's start time to now?"
+                                ),
+                                "slot": Icon("reset"),
+                                "title": "Reset start to now",
+                                "color": "gray",
+                            }
+                            if session.timestamp_end is None
+                            else {},
                             {
                                 "href": reverse(
                                     "games:edit_session", args=[session.pk]
@@ -379,6 +397,20 @@ def end_session(request: HttpRequest, session_id: int) -> HttpResponse:
     return redirect("games:list_sessions")
 
 
+@login_required
+def reset_session_start(request: HttpRequest, session_id: int) -> HttpResponse:
+    session = get_object_or_404(Session, id=session_id)
+    session.timestamp_start = timezone.now()
+    session.save()
+    if request.htmx:
+        # The list table is rebuilt server-side per request; a full refresh
+        # avoids swapping in a row fragment whose layout could drift from it.
+        response = HttpResponse(status=204)
+        response["HX-Refresh"] = "true"
+        return response
+    return redirect("games:list_sessions")
+
+
 @login_required
 def delete_session(request: HttpRequest, session_id: int = 0) -> HttpResponse:
     session = get_object_or_404(Session, id=session_id)