Fix the referee PDF's card background, make locations searchable, and add game end times to the API

Referee PDF: the info-card background used CSS color-mix(), which WeasyPrint
doesn't support -- the rule was silently dropped, leaving the card with no
background at all. Computed in Python instead (management/pdf.py) and baked
into the template as a plain hex value; the tint is based on the club's
primary_color, falling back to secondary_color when primary is itself (near)
black or white, where a straight tint would be invisible or too harsh.

Event forms: the location picker now shows "Name — City" (plus the country
when it isn't Belgium) and is searchable by name or city, reusing the
existing single-select searchable-select.js widget.

Games API: GameOut now carries `end` (explicit, or start + 2h when a GAME was
saved without one -- Event.save() sets this, never overwriting an explicit
end; other event kinds are untouched). /games/upcoming/ now includes
anything not yet finished rather than only things that haven't started, so a
game already in progress keeps showing up until its window closes; `status`
was adjusted to match so a game returned there never calls itself
"finished".

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

api/tests.py

@@ -356,6 +356,32 @@ class GamesApiTests(ApiTestBase):
 
         self.assertEqual(self.api_get("/games/upcoming/").json(), [])
 
+    def test_upcoming_includes_a_game_already_in_progress(self):
+        # Started 30 minutes ago, no explicit end -- the assumed 2h window
+        # means it isn't finished yet, so it must still show up.
+        self.make_game(start=timezone.now() - datetime.timedelta(minutes=30))
+
+        games = self.api_get("/games/upcoming/").json()
+
+        self.assertEqual(len(games), 1)
+        self.assertEqual(games[0]["status"], "live")
+
+    def test_upcoming_excludes_a_game_past_its_explicit_end(self):
+        game = self.make_game(start=timezone.now() - datetime.timedelta(hours=3))
+        game.end = timezone.now() - datetime.timedelta(hours=1)
+        game.save()
+
+        self.assertEqual(self.api_get("/games/upcoming/").json(), [])
+
+    def test_the_response_includes_an_end_time(self):
+        game = self.make_game()
+
+        end = self.api_get("/games/upcoming/").json()[0]["end"]
+
+        # JSON round-trips to millisecond precision -- compare with a small
+        # tolerance rather than an exact microsecond match.
+        self.assertLess(abs((datetime.datetime.fromisoformat(end) - game.end).total_seconds()), 1)
+
     def test_upcoming_includes_tournaments(self):
         self.make_game(kind=Event.EventKind.TOURNAMENT)