feat(utils): implement async rsync wrapper with RsyncOptions

[sushant-suse]

Addresses #452

What was done:

• Created RsyncOptions Dataclass: Implemented a flexible configuration class in docbuild.utils.sync to handle common rsync flags (archive, delete, dry_run, etc.) alongside an extra_args list, preventing function signature bloat while maintaining full CLI flexibility.
• Implemented Async rsync Wrapper: Created an asynchronous rsync() function that wraps docbuild.utils.shell.run_command to execute synchronization tasks safely and concurrently.
• Smart Trailing Slash Handling: Added path inspection to automatically infer if the user intends to sync a directory or just its contents based on the presence of a trailing slash, with an explicit content_only override parameter.
• Registered System Dependency: Added rsync to the SYSTEM_DEPENDENCIES dictionary in constants.py so it is automatically verified by the docbuild doctor command.
• Added Comprehensive Tests: Wrote isolated unit tests verifying argument generation, trailing slash behavior, and Path object compatibility.
• Resolved Type Warnings: Fixed a pedantic Pylance strict-typing error regarding Enum.name types in constants.py.

@tomschr, as we discussed, I kept this PR strictly focused on the core rsync utility implementation to keep a clean separation of concerns. Once this is merged, I will open the next PR to actually integrate this into the build subcommand logic.

Checklist

• Code is properly formatted (uvx ruff check --fix and uvx ruff format)
• Tests have been updated and are passing locally
• A changelog entry was added to changelog.d/
• Documentation has been updated (N/A for this PR)

[github-actions]

Coverage Report

For commit 124ae24

Click to expand Coverage Report

  Name                                          Stmts   Miss Branch BrPart  Cover
  -------------------------------------------------------------------------------
+ src/docbuild/tasks/portal.py                    140      0     50      1  99.5%
+ src/docbuild/models/manifest.py                 156      1     32      1  98.9%
+ src/docbuild/logging.py                         104      1     26      1  98.5%
+ src/docbuild/utils/pidlock.py                    79      1     14      1  97.8%
+ src/docbuild/cli/cmd_config/list.py              28      0     10      1  97.4%
+ src/docbuild/cli/cmd_portal/cmd_list.py         168      1     86      7  96.9%
+ src/docbuild/models/deliverable/__init__.py      95      2     14      2  96.3%
+ src/docbuild/models/deliverable/view.py         175      3     48      6  96.0%
+ src/docbuild/cli/callback.py                     35      0     10      2  95.6%
+ src/docbuild/utils/concurrency.py                65      3     18      1  95.2%
+ src/docbuild/tasks/metadata/runner.py            65      3     16      1  95.1%
+ src/docbuild/cli/cmd_cli.py                     142      7     28      6  92.4%
+ src/docbuild/utils/sync.py                       46      3     14      2  91.7%
+ src/docbuild/cli/cmd_metadata/__init__.py        41      2      4      2  91.1%
- src/docbuild/cli/cmd_doctor.py                   37      4     10      2  87.2%
- src/docbuild/tasks/build/runner.py               88     14     16      3  83.7%
- src/docbuild/tasks/metadata/manifest.py         130     16     48      6  83.1%
- src/docbuild/cli/cmd_config/validate.py          21      2     12      3  78.8%
- src/docbuild/cli/cmd_check/__init__.py           22      9      4      0  50.0%
- src/docbuild/cli/cmd_build/__init__.py           59     38      8      0  31.3%
  -------------------------------------------------------------------------------
+ TOTAL                                          3983    110   1088     48  96.5%
  
  58 files skipped due to complete coverage.

[tomschr]

Great work! 👍

I have some small comments for you.

[tomschr]

Looks great! Thank you very much, Sushant! 👍

Please merge it!