Add -p short alias for --param in luca run

[albertodebortoli]

Description

The original ask was to improve the UX of luca run so parameters could be passed without the --param flag at all, e.g.:

luca run build flavour=release upload=true

instead of the current:

luca run build --param flavor=release --param upload=true

We explored a few options before landing on this PR's approach:

1. Bare key=value positional arguments (the original ask). Implemented as an @Argument array trailing the existing optional <name> argument. This reads naturally, but ArgumentParser fills positional arguments greedily in declaration order: with <name> as an optional scalar positional followed by an array positional, a bare key=value token given while using --file (which is mutually exclusive with <name>) would get wrongly assigned to name instead of to the params array — e.g. luca run --file x.yml flavor=release would set name = "flavor=release". This is a real, silent-failure-shaped edge case, not just a corner case to document away.
2. Detect-and-reinterpret: keep the bare positional form, but add logic in validate()/run() to notice when name itself looks like KEY=VALUE and --file is set, and reclassify it as a param. This resolves the ambiguity but adds parsing "magic" that's surprising and harder to reason about/test.
3. Add -p as a short-name alias for --param (chosen). No positional parsing ambiguity, no magic, fully backward compatible with existing scripts/CI using --param. Slightly less terse than the original ask, but a much safer change:

   luca run build -p flavor=release -p upload=true
   

Given the risk profile of option 1/2 versus the low-risk, high-value option 3, we went with the -p alias.

Type of Change

• Feature
• Bug fix
• Maintenance / Refactor
• Documentation
• CI / Tooling
• Other (specify)

How Has This Been Tested?

• Manually tested locally (swift build, then luca run --file test.yml -p flavor=release -p upload=true --dry-run, verified both params resolved as overrides)
• Added / updated unit tests (no existing unit test coverage for RunCommand argument parsing; behavior verified manually and via full test suite)
• Tested on macOS (arch: arm64)
• Full swift test suite passes (581 tests)

Screenshots / Demo (if applicable)

N/A (CLI flag change)

Checklist

• Swift code builds locally (swift build)
• Tests pass locally (swift test)
• Code style / formatting respected
• Documentation updated (README / comments)
• Version / tag alignment considered (if release related)
• PR title follows conventional style (optional)

CI Considerations

• Affects build time notably
• Requires new secrets / env vars
• Alters release process

Breaking Changes?

• No
• Yes (describe impact and migration path)

Additional Notes

--param continues to work exactly as before; -p is purely additive.