Implement flake8 rules

- [ ] S404 # Consider possible security implications associated with the subprocess module.
- [ ] S108 # Probable insecure usage of temp file/directory.
- [ ] S307 # Use of possibly insecure function - consider using safer ast.literal_eval.
- [ ] S603 # subprocess call - check for execution of untrusted input.
- [ ] S607 # Starting a process with a partial executable path ["open" in both cases]
- [ ] S608 # Possible SQL injection vector through string-based query construction.

The issue lists six unchecked security rules: S404, S108, S307, S603, S607, and S608. Start by locating the reported usages in the Python repository and reviewing the affected code paths. Done means all six listed findings are addressed and the checks no longer report them.

Written by the indexing model from the issue text.