What's New in v2.6.1 🛡️ COM Crash Fix & Null-Safety Audit

🔥 Critical Fix: `Unable to set the Calculation property` Crash

The v2.5.9 Silent Mode optimization (excel.Calculation = xlCalculationManual) crashes on certain Excel installations
Fix: Each Silent Mode flag (ScreenUpdating, Calculation, EnableEvents) is now wrapped in individual try/except blocks
If one flag fails, the others still apply and Excel still launches successfully
A warning is logged so users can see which flags their Excel version doesn't support

xlrd pre-scan path: str(c.value).strip() now uses defensive str(c.value).strip() if c.value is not None else ""
Prevents None cells from becoming the literal string "None" (which could false-match column headers)
All cell-read paths across com_engine.py and engine.py audited and confirmed null-safe

Module	Path	Status
`com_engine.py` header scan (L466)	`str(v).strip() if v is not None else ""`	✅ Already safe
`com_engine.py` currency read (L531)	`str(raw).strip().upper() if raw else ""`	✅ Already safe
`com_engine.py` date parser	Guards against None via `_parse_cell_date()`	✅ Already safe
`engine.py` xlrd pre-scan (L396)	Was `str(c.value).strip()`	🔧 Fixed
`engine.py` openpyxl scan (L435)	`str(c).strip() if c is not None else ""`	✅ Already safe
`prescan.py` header scan (L131)	`str(c).strip() if c is not None else ""`	✅ Already safe