[CLI] Make per-run log files unique by appending timestamp + open with mode="w" (fixes #984)

[abhisheksingh-esp]

Fixes #984.

Root cause: configure_logger_for_run in
certification-tool-cli/th_cli/test_run/logging.py derived the log file path
solely from --title (test_run_{title}.log) and loguru.logger.add(...)
defaults to append mode. Reusing -n NAME across runs caused successive runs
to be concatenated into the same file.
Change:

• Append a timestamp suffix (_YYYY-MM-DD-HH-MM-SS) to the log filename inside
  configure_logger_for_run, so every run produces a unique file regardless
  of the -n NAME value (matches the convention suggested by @OlivierGre).
• Pass mode="w" to logger.add(...) as defense-in-depth, in case two runs
  ever land on the exact same path (e.g. same second).
  No public API change; configure_logger_for_run(title) still returns the
  resolved path used by run_tests at the end of execution.
  Verification:
• Run the same test twice with -n my_run. Two distinct files in run_logs/,
  each containing only its own run.

[CLAassistant]

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[gemini-code-assist]

Code Review

This pull request updates the logging configuration to include a timestamp in log filenames and sets the file mode to write. A review comment identifies a potential portability issue on Windows systems where the 'title' parameter might contain invalid characters like colons, and provides a code suggestion to sanitize the string.

[antonio-amjr]

Hi @abhisheksingh-esp,

Seems good, but I would like to ask for a little change if I may.
Let me know what you think of the suggestion below.