fix(ci): lint ruff 0.16.3 - imports tries, check explicite, removeprefix

- backend/main.py : split import csv / import io as csv_io (I001)

- backend/version.py : check=False explicite sur subprocess.run (PLW1510)

- backend/version.py : tag.removeprefix() au lieu du slice conditionnel (FURB188)

- verifie localement avec ruff 0.16.3 : All checks passed!

backend/main.py

@@ -2484,7 +2484,8 @@ async def api_file(vault_name: str, path: str = Query(..., description="Relative
 
     # === CSV: render as HTML table ===
     if ext == ".csv":
-        import csv, io as csv_io
+        import csv
+        import io as csv_io
         reader = csv.reader(csv_io.StringIO(raw))
         rows = list(reader)
         if not rows: