restore and rebuild all stock query scripts

Recover 7 existing scripts from remote repo and rebuild 5 missing ones:
- twse-margin-trading.py (融資融券)
- twse-day-trading.py (當沖交易)
- twse-foreign-holdings.py (外資持股)
- yahoo-dividend-browserless.py (股利資訊)
- yahoo-broker-trading-browserless.py (主力券商進出)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,19 @@
+# Python
+__pycache__/
+*.py[cod]
+*$py.class
+*.so
+.Python
+*.egg-info/
+dist/
+build/
+
+# IDE
+.vscode/
+.idea/
+*.swp
+*.swo
+
+# OS
+.DS_Store
+Thumbs.db