Create workflow to submit solution

[brendanator]

• Create GitHub workflow called submit-advent-of-code.yml
• Trigger on
  • Push to main with file changes to puzzles/year_*/day_*/answer_part*.txt
  • workflow_dispatch
• Set env vars
  • AOC_SESSION: secrets.AOC_SESSION
  • GH_TOKEN: secrets.USER_TOKEN
• Set up
  • Check out repo - uses: actions/checkout@v4
  • Setup uv - uses astral-sh/setup-uv@v4 and uv sync
• Set concurrency to only run one at a time in this repo and don't cancel in progress runs
• Add permissions needed: content, issues
• Submit solution using uv run advent_of_code.py submit {year} {day} {part}
  • Mark this step as successful even if the exit code was 1
• Update results section in README.md by running uv run advent_of_code.py update-results {year}
• If it was part 1 and the submission was correct:
  • download part two with uv run advent_of_code.py download {year} {day} and output the part which is printed by the command
• Commit and push puzzles in puzzles with user GitHub Actions
• Trigger create-puzzle-issue.yml using the year, day and part 2 as strings if part two was downloaded
  • uses: sourcery-ai/autonomous-advent-of-code/.github/workflows/create-puzzle-issue.yml@main