Add BLDI pressure gauge classification tool

Implement VBA-based Excel tool for automatic classification of
pressure gauge model codes into 9 product categories.

Features:
- GaugeClassifier class with parsing and classification logic
- MainModule for Excel I/O with bulk array operations
- TestModule with comprehensive test suite (12 test cases)
- Complete documentation (README, INSTALL, algorithm guide)

Categories: 喷涂产品, 卫生型隔膜表, 隔膜表, 差压表,
膜盒压力表, 精密压力表, 电接点压力表, 常规表, 其他

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

.gitignore

@@ -0,0 +1,23 @@
+# Claude Code
+.claude/
+
+# VS Code
+.code-workspace/
+*.code-workspace
+
+# Excel files
+*.xlsx
+*.xlsm
+*.xls
+*.xlam
+
+# Excel temporary files
+~$*
+*.tmp
+
+# OS files
+.DS_Store
+Thumbs.db
+
+# VBA backup files
+*.bak