feat: add examples (01-08), fix index bars parsing, add ruff hook

- Add example scripts for all API categories (connection, market info,
  kline, minute, transaction, finance, block, fund flow)
- Fix GetIndexBarsCmd: index bar records have 4 extra bytes (advance/
  decline counts) that were not consumed, causing pos drift and
  corrupted dates/volumes for all records after the first
- Fix price_limits.py example (SecurityQuote has no name attr)
- Fix finance_info.py display (scientific notation -> formatted numbers)
- Add PostToolUse ruff hook (scripts/ruff_hook.py)

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

examples/03_kline/security_bars.py

@@ -0,0 +1,23 @@
+"""演示：获取个股 K 线数据。
+
+K 线类别:
+  KlineCategory.MIN_1  / MIN_5  / MIN_15 / MIN_30 / MIN_60
+  KlineCategory.DAY    / WEEK   / MONTH  / YEAR
+"""
+
+import pandas as pd
+from xmtdx import TdxClient, Market, KlineCategory
+
+with TdxClient.from_best_host() as c:
+    bars = c.get_security_bars(Market.SZ, "002176", KlineCategory.DAY, 0, 100)
+    df = pd.DataFrame([{
+        "日期": f"{b.year}-{b.month:02d}-{b.day:02d}",
+        "开盘": b.open,
+        "最高": b.high,
+        "最低": b.low,
+        "收盘": b.close,
+        "成交量": b.vol,
+        "成交额": b.amount,
+    } for b in reversed(bars)])
+    print("上证指数 日K线:")
+    print(df.to_string(index=False))