[Bug] Skill naming warnings do not clarify that namespaced skills still load

[BleedingDev]

Affected area

Coding agent and CLI; TUI

What happened?

Startup shows one warning per shared ui:* skill (nine in my setup):

auto (user) ~/.agents/skills/ui:design/SKILL.md
  name contains invalid characters (must be lowercase a-z, 0-9, hyphens only)

I only noticed this warning in Prime Agent. It is unclear from the warning whether the skills remain usable.

Steps to reproduce

1. Create ~/.agents/skills/ui:design/SKILL.md:

   ---
   name: ui:design
   description: Minimal naming example.
   ---
   Follow the user's design request.

2. Start prime-agent and inspect Skill Warnings.

Expected behavior

Keep standards validation, but say that the skill still loaded and suggest a portable name such as ui-design (rename both directory and frontmatter).

Investigation

• The Agent Skills standard excludes : from frontmatter names. This warning is standards-correct, not evidence of a loader failure.
• Claude Code documents namespaced commands and prefixed plugin frontmatter. Claude-specific support is not portable-standard compliance; other clients were not runtime-tested here.
• Prime Agent's validator warns; the loader still returns the skill. Its test explicitly expects this.
• Directly reproduced using the installed 0.9.3 loadSkillsFromDir: ui:design returns one markdown skill plus the warning. A valid actionlint control returns one skill with no diagnostics.

Scope: warning clarity / cross-client compatibility, not a request to declare colons standard-compliant.

Environment

• Prime Agent version: 0.9.3
• Installation method: npm package (global installation)
• Operating system: macOS 26.7 (25G224)
• CPU architecture: arm64
• Shell and terminal: zsh; original terminal application not recorded

[awhite0030]

Investigated this report and produced a candidate fix, validated on a fork of this repository.

Root cause, fix and validation from the working notes:

Root cause: The existing warning message for invalid characters in skill names (ui:design) was confusing, leaving it ambiguous whether the skill was actually loaded and usable.
Fix: Updated the diagnostic warning in validateName to explicitly state that the skill "was still loaded". Also, added logic to auto-generate a valid, standard-compliant fallback name using regex (replacing non-standard characters with hyphens) to guide the user on renaming the skill properly.
Validation: Wrote a focused regression test (skill-naming-warning.test.ts) that asserts both the successful load of a colon-named skill and the specific textual pattern of the updated diagnostic message. Ran the existing test suite (test/skills.test.ts) and npm run check, all of which successfully passed.
Upstream discussion: #2104

Diff: awhite0030/prime-agent@main...fix-skill-naming-warning-13208057976626092218
Full pull request: awhite0030#64

The change passes npm run check and the focused regression tests against current main. If a fix for this is still wanted, I can open a pull request.