fix(skills): remove references to missing CLI commands

[jiangyq9]

What & why

The installed skill files currently tell agents to run CLI commands that do not exist in the current git-ai command surface, especially git-ai search, git-ai continue, and git-ai prompts. When an agent follows those instructions, the skill fails at runtime instead of using the supported note-backed inspection commands.

Root cause

The skill docs drifted ahead of the CLI. git-ai currently exposes supported commands such as log, show, diff, blame, stats, and show-prompt, but these skills were written around planned search / continue / prompts flows.

Change

• Rewrite skills/git-ai-search/SKILL.md around supported commands only:
  • git-ai show
  • git-ai diff --json --include-stats --all-prompts
  • git-ai blame --show-prompt
  • git-ai stats --json
  • git-ai show-prompt
• Rewrite skills/prompt-analysis/SKILL.md to remove the unsupported prompts.db / git-ai prompts workflow.
• Update skills/ask/SKILL.md so it uses git-ai blame --show-prompt instead of git-ai search.
• Add explicit guardrails telling agents not to call unsupported commands from these skills.

Testing

• Not run (docs-only skill updates).

Fixes #1307

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[CLAassistant]

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[devin-ai-integration]

Devin Review found 1 new potential issue.