Apply velvet-table redesign, fix game lifecycle and history bugs

Frontend:
- Dark green/gold "velvet table" visual redesign across the whole app
  (Auth, Lobby, GameList, GameTable, History, GameOver, modals), with
  Playfair Display/DM Sans typography and a centralized Tailwind palette.
- Desktop game table fit-scales to fill the window; mobile gets
  overlapping hand/trick layouts and larger touch-friendly cards.
- Standings sidebar now groups completed rounds by series with a
  per-series subtotal row, struck-through tips on missed bids.
- History page rewritten into a scoreboard-style detail view (player
  totals beside names, series grouped 2-up on desktop / stacked on
  mobile) and gained game names, completed/abandoned status, and a
  button to reopen a prematurely-ended game back into the lobby.

Backend:
- Fix started games being deleted from memory (and vanishing from
  everyone's lobby) when all players disconnect; only `end_game` tears
  down a started game now.
- Fix a crash writing a timezone-aware datetime into the naive
  `ended_at` Postgres column.
- Add `reopen_game`/`restore_game` to un-end a prematurely-ended game
  from history and resume it from the lobby.
- Let any seated player end an abandoned game once the host is
  offline, not just the host, so the game isn't stuck forever.
- Expose SERIES_PER_GAME/ROUNDS_PER_SERIES as named constants on the
  engine so the persistence layer derives game-completion rules from
  bridzik.py instead of re-encoding them.

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

tests_history.py

@@ -143,15 +143,41 @@ class HistoryCase(unittest.TestCase):
         run(history.mark_game_ended(gid))
         self.assertFalse(any(g["gid"] == gid for g in run(history.get_unfinished_games())))
 
+    def test_reopen_prematurely_ended_game(self):
+        ids = self._make_players()
+        gid = str(uuid.uuid4())
+        run(history.record_game_started(gid, "Vzdana", ids))
+        run(history.record_completed_rounds(gid, make_core(completed=False)))
+        run(history.mark_game_ended(gid))
+
+        # V historii sa ukazuje ako predcasne ukoncena (nie naplno dohrana).
+        rows = run(history.get_player_history(ids[0]))
+        mine = next(g for g in rows if g["gid"] == gid)
+        self.assertFalse(mine["completed"])
+
+        # Cudzi hrac ju obnovit nemoze.
+        outsider = self._make_players(1)[0]
+        self.assertIsNone(run(history.reopen_game(gid, outsider)))
+
+        # Clen ju obnovi -> ended_at sa zmaze a hra je zas medzi nedohratymi.
+        info = run(history.reopen_game(gid, ids[0]))
+        self.assertIsNotNone(info)
+        self.assertEqual(len(info["seats"]), 4)
+        self.assertTrue(any(g["gid"] == gid for g in run(history.get_unfinished_games())))
+        # A teda uz nie je v historii (zobrazuju sa iba ukoncene hry).
+        self.assertFalse(any(g["gid"] == gid for g in run(history.get_player_history(ids[0]))))
+
     def test_standings_from_db(self):
         ids = self._make_players()
         gid = str(uuid.uuid4())
         run(history.record_game_started(gid, "Test", ids))
         run(history.record_completed_rounds(gid, make_core()))
 
-        standings = run(history.get_standings(gid))
-        # 1 seria, 1 kolo, body podla sedadiel zo stubu [12, 0, 10, 11].
+        standings, guesses = run(history.get_standings(gid))
+        # 1 seria, 1 kolo. Body podla sedadiel zo stubu [12, 0, 10, 11],
+        # tipy zo stubu {0: 2, 1: 1, 2: 0, 3: 1}.
         self.assertEqual(standings, [[[12, 0, 10, 11]]])
+        self.assertEqual(guesses, [[[2, 1, 0, 1]]])
 
     def test_player_history(self):
         ids = self._make_players()