Add proto validation for names

[eleftherias]

Summary

For stacklok entity names (profile, provider, etc) the pattern is [A-Za-z][-[:word:]]*, must start with a letter and may contain dashes, underscores and alphanumeric characters.

For display names the pattern is [[:space:][:punct:][:word:]]*, the characters used to form a sentence.

For external names (repo, artifact, etc) the pattern is [-./[:word:]]*, alphanumeric characters, dashes, underscores, plus dots and slashes.

Ref stacklok/minder-stories#94

Change Type

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• Bug fix (resolves an issue without affecting existing features)
• Feature (adds new functionality without breaking changes)
• Breaking change (may impact existing functionalities or require documentation updates)
• Documentation (updates or additions to documentation)
• Refactoring or test improvements (no bug fixes or new functionality)

Testing

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Review Checklist:

• Reviewed my own code for quality and clarity.
• Added comments to complex or tricky code sections.
• Updated any affected documentation.
• Included tests that validate the fix or feature.
• Checked that related changes are merged.

[coveralls]

Pull Request Test Coverage Report for Build 11704048485

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

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• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.007%) to 54.77%

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Totals
Change from base Build 11701614228:	0.007%
Covered Lines:	15536
Relevant Lines:	28366

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💛 - Coveralls