feat: improve license workflows

[beanrepo]

Refine license automation in app-bricks-examples by separating REUSE and licensed responsibilities in both Taskfile and CI, while preserving the repo’s current licensing setup and virtualenv cleanup behavior.

What's included

• Taskfile.dist.yml

  • splits the old monolithic license flow into:
    • license:headers for REUSE annotations, license downloads and REUSE linting
    • license:deps for licensed cache + licensed status
  • keeps license as a backward-compatible aggregate task chaining license:headers -> license:deps
  • keeps init:license and init:ci as backward-compatible entry points
  • adds dedicated internal tasks to create and clean up the REUSE and licensed virtualenvs separately
  • keeps cleanup of the virtualenvs in this repo after the tasks complete
  • keeps install:licensed and updates its messaging to point to task license:deps
  • adds non-blocking warnings when requirements cannot be installed in the dependency-scanning venv

• .github/workflows/license.yml

  • splits license validation into two jobs:
    • check-license-headers for REUSE/header validation
    • check-dependency-licenses for licensed
  • keeps the stable-version validation for the pinned arduino_app_bricks wheel
  • makes dependency-license failures depend on actual licensed status errors instead of raw git diff
  • adds multiline GitHub Actions annotations for real dependency-license errors
  • adds a detailed step summary with:
    • blocking dependency license issues
    • non-blocking dependency installation warnings
    • non-blocking cached record updates / outdated dependency versions

Notes

• The existing .licensed.yml and REUSE.toml configuration are intentionally preserved.
• Warning extraction in CI was made robust for this repo’s requirements.txt, including requirement lines with URLs such as:
  • arduino_app_bricks @ https://...
• REUSE/header checks still rely on file diffs, while dependency-license checks now rely on the semantic result of licensed status.

[robgee86]

LGTM, a plus would be to align the task names and dev workflow to the one in this PR.