chore(logging): enable gzipped log rotation and adjust test logging

[Ludy87]

Description of Changes

This PR improves log retention and disk usage management by compressing rotated log files and applying explicit retention limits.

• Updated the Logback rolling policies for authentication and application logs:
  • Rotated auth logs are now stored as .log.gz files.
  • Rotated info logs are now stored as .log.gz files.
  • Increased retention from 1 day to 7 days for both log types.
  • Added a 64MB total size cap for authentication log archives.
  • Added a 256MB total size cap for application log archives.
• Added *.log.gz to app/core/.gitignore so compressed log archives are not accidentally committed.
• Updated Gradle test logging:
  • Removed started test events from the output.
  • Added skipped test events.
  • Failed tests continue to be reported with exception, cause, and stack trace information.

The change was made to retain useful historical logs for longer while reducing their storage footprint and preventing archived logs from growing without bounds. The Gradle logging adjustment also reduces unnecessary test output while making skipped tests visible.

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Checklist

General

• I have read the Contribution Guidelines
• I have read the Stirling-PDF Developer Guide (if applicable)
• I have read the How to add new languages to Stirling-PDF (if applicable)
• I have performed a self-review of my own code
• My changes generate no new warnings

Documentation

• I have updated relevant docs on Stirling-PDF's doc repo (if functionality has heavily changed)
• I have read the section Add New Translation Tags (for new translation tags only)

Translations (if applicable)

• I ran scripts/counter_translation.py

UI Changes (if applicable)

• Screenshots or videos demonstrating the UI changes are attached (e.g., as comments or direct attachments in the PR)

Testing (if applicable)

• I have run task check to verify linters, typechecks, and tests pass
• I have tested my changes locally. Refer to the Testing Guide for more details.

[stirlingbot]

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