feat: add Textual TUI with auto-refresh, leaders, playoff picture, and box score

Introduces an interactive terminal UI via the `--tui` flag backed by the
Textual framework. Scores and standings auto-refresh on a configurable
interval (default 60s, minimum 10s) using asyncio with nba_api calls
offloaded to a thread pool to keep the event loop unblocked.

New tabs:
- Scores / Standings (existing views, now live-updating)
- Leaders: top-25 by stat category, cycle with < / > keys
- Playoff Picture: conference seeding with clinch/elimination status
- Box Score: per-player live stats, load any game with keys 1–9

Refactored scores.py and standings.py to separate rendering from I/O
(get_scoreboard_table, get_east/west_standings_table), keeping the
existing static CLI path fully intact. Added -sc / -st shortcut flags.

Adds textual>=0.89.1,<7.0 dependency, build-system declaration for uv,
and package-data entry for the bundled .tcss stylesheet.

1 files changed, 72 insertions, 0 deletions

diff --git a/nba/leaders.py b/nba/leaders.py
new file mode 100644
index 0000000..aa6f3b4
--- /dev/null
+++ b/nba/leaders.py
@@ -0,0 +1,72 @@
+"""
+Fetches and formats NBA statistical leaders.
+"""
+
+import json
+
+from tabulate import tabulate
+from nba_api.stats.endpoints.leagueleaders import LeagueLeaders
+
+BOLD = "\033[1m"
+END = "\033[0m"
+
+# Ordered list of (api_abbreviation, display_label)
+CATEGORIES = [
+    ("PTS", "Points"),
+    ("REB", "Rebounds"),
+    ("AST", "Assists"),
+    ("STL", "Steals"),
+    ("BLK", "Blocks"),
+    ("EFF", "Efficiency"),
+    ("FG_PCT", "FG%"),
+    ("FT_PCT", "FT%"),
+    ("FG3_PCT", "3P%"),
+]
+
+# Extra columns to show alongside RANK, PLAYER, TEAM, GP for each category
+_EXTRA_COLS = {
+    "PTS":    ["PTS", "FGM", "FGA", "FG_PCT", "FTM", "FTA", "FT_PCT"],
+    "REB":    ["REB", "OREB", "DREB", "GP"],
+    "AST":    ["AST", "TOV", "AST_TOV", "GP"],
+    "STL":    ["STL", "TOV", "GP"],
+    "BLK":    ["BLK", "PF", "GP"],
+    "EFF":    ["EFF", "PTS", "REB", "AST", "GP"],
+    "FG_PCT": ["FG_PCT", "FGM", "FGA", "PTS"],
+    "FT_PCT": ["FT_PCT", "FTM", "FTA", "PTS"],
+    "FG3_PCT":["FG3_PCT", "FG3M", "FG3A", "PTS"],
+}
+
+_DISPLAY_NAMES = {
+    "FG_PCT": "FG%", "FT_PCT": "FT%", "FG3_PCT": "3P%",
+    "FG3M": "3PM", "FG3A": "3PA",
+    "AST_TOV": "AST/TO",
+}
+
+
+def fetch_leaders(category: str = "PTS") -> dict:
+    endpoint = LeagueLeaders(
+        stat_category_abbreviation=category,
+        season_type_all_star="Regular Season",
+    )
+    return json.loads(endpoint.get_json())
+
+
+def get_leaders_table(data: dict, category: str = "PTS") -> str:
+    result = data["resultSet"]
+    headers = result["headers"]
+    rows = result["rowSet"]
+
+    base = ["RANK", "PLAYER", "TEAM", "GP"]
+    extra = [c for c in _EXTRA_COLS.get(category, [category]) if c not in base]
+    wanted = base + extra
+
+    idx = {h: i for i, h in enumerate(headers)}
+    table_data = [
+        [row[idx[col]] for col in wanted if col in idx]
+        for row in rows[:25]
+    ]
+    display_headers = [_DISPLAY_NAMES.get(c, c) for c in wanted if c in idx]
+
+    cat_label = dict(CATEGORIES).get(category, category)
+    title = f"{BOLD}League Leaders — {cat_label}{END}"
+    return title + "\n" + tabulate(table_data, headers=display_headers, tablefmt="grid")