Satisfy CI lint on touched files

The Lint job runs ruff (modern defaults) over every changed file, so the
pre-existing violations in documentation_generator.py and prompt_template.py
count against this PR. Mechanical cleanup only: import sorting, ruff format,
Dict/List -> dict/list, explicit Optional, timezone-aware metadata timestamp,
no mutable argument defaults, and dropping two duplicated dict keys
(".hpp"/".jsx" in EXTENSION_TO_LANGUAGE). The two intentional blanket
`except Exception` handlers are noqa'd with justification.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: anhnh2002