docs: explain timestamp and asctime formatting

[arindamsikder]

Summary

Add a dedicated Logging Time guide and link it from the documentation navigation.

Problem

In #17, readers were unsure whether timestamp was supported, whether it emitted an epoch number or ISO 8601 string, and how it differed from asctime. The discussion explicitly welcomes a separate page documenting the current behavior.

Solution

• Explain UTC timestamp values, custom field names, and why putting timestamp in fmt alone produces null.
• Explain asctime, datefmt, UTC conversion, fractional seconds, and field-name collisions without changing their behavior.
• Include reproducible formatter outputs and a complete dictConfig example, including the boolean-versus-string configuration distinction.

This is documentation only: no runtime, dependency, version, or time-format contract changes.

Testing

Validation ran on Python 3.11 in a credential-free, network-isolated Bubblewrap environment:

• python -m pytest tests -q -p no:cacheprovider --basetemp=/tmp/pytest — 221 passed on both the unchanged base and the final tree.
• Executed all five Python code blocks verbatim; all four displayed JSON outputs matched. Verified the dictConfig output fields and an aware UTC timestamp within the actual execution window.
• Checked default exclusion, timestamp collision precedence, datefmt/converter independence and string-key behavior with the stdlib JSON, orjson and msgspec formatters.
• python -m black --check --diff src tests — passed (14 files unchanged; Black emitted a Python-target-version warning).
• python -m pylint src — passed, 10.00/10.
• python -m mypy src tests --cache-dir /tmp/mypy-cache — passed, 14 source files.
• python -m mkdocs build --site-dir /out/final-site — completed; rendered the new page and verified its navigation link. The seven pre-existing annotation warnings and unavailable external Python inventory diagnostic were identical on the unchanged base. The inventory cannot be downloaded in the offline sandbox.
• git diff --check and independent automated diff review — passed.

The current unpinned Python docs handler 2.0 rejected the existing import configuration. For both baseline and final documentation builds, I used mkdocstrings 0.30.1, mkdocstrings-python 1.18.2, and mkdocs-gen-files 0.5.0. No dependency pins were added to this PR. Other Python versions and operating systems were not run locally.

Related Issue

Related to #17 — addresses the requested documentation, not the broader possible behavior changes discussed there.

AI assistance

Prepared by Hermes DEV using OpenAI GPT-6 Astra, including the documentation, local validation and an independent automated diff review. No human review is claimed.