Refactor card values to single source of truth, fix ten_penny bug

- Add constants.py as the single source of truth for card values
- Derive RANK_VALUES from DEFAULT_CARD_VALUES instead of duplicating
- Add centralized get_card_value() function in game.py for Card objects
- Add get_card_value_for_rank() in constants.py for string-based lookups
- Fix bug: AI ten_penny returned 0 instead of 1 per RULES.md
- Update ai.py and game_analyzer.py to use centralized functions
- UI improvements for client

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

server/constants.py

@@ -0,0 +1,53 @@
+# Card values - Single source of truth for all card scoring
+# Per RULES.md: A=1, 2=-2, 3-10=face, J/Q=10, K=0, Joker=-2
+DEFAULT_CARD_VALUES = {
+    'A': 1,
+    '2': -2,
+    '3': 3,
+    '4': 4,
+    '5': 5,
+    '6': 6,
+    '7': 7,
+    '8': 8,
+    '9': 9,
+    '10': 10,
+    'J': 10,
+    'Q': 10,
+    'K': 0,
+    '★': -2,  # Joker (standard)
+}
+
+# House rule modifications (per RULES.md House Rules section)
+SUPER_KINGS_VALUE = -2        # K worth -2 instead of 0
+LUCKY_SEVENS_VALUE = 0        # 7 worth 0 instead of 7
+TEN_PENNY_VALUE = 1           # 10 worth 1 instead of 10
+LUCKY_SWING_JOKER_VALUE = -5  # Joker worth -5 in Lucky Swing mode
+
+
+def get_card_value_for_rank(rank_str: str, options: dict | None = None) -> int:
+    """
+    Get point value for a card rank string, with house rules applied.
+
+    This is the single source of truth for card value calculations.
+    Use this for string-based rank lookups (e.g., from JSON/logs).
+
+    Args:
+        rank_str: Card rank as string ('A', '2', ..., 'K', '★')
+        options: Optional dict with house rule flags (lucky_swing, super_kings, etc.)
+
+    Returns:
+        Point value for the card
+    """
+    value = DEFAULT_CARD_VALUES.get(rank_str, 0)
+
+    if options:
+        if rank_str == '★' and options.get('lucky_swing'):
+            value = LUCKY_SWING_JOKER_VALUE
+        elif rank_str == 'K' and options.get('super_kings'):
+            value = SUPER_KINGS_VALUE
+        elif rank_str == '7' and options.get('lucky_sevens'):
+            value = LUCKY_SEVENS_VALUE
+        elif rank_str == '10' and options.get('ten_penny'):
+            value = TEN_PENNY_VALUE
+
+    return value