Remove undefined agent directive from command frontmatter

[Copilot]

Command files referenced a non-existent agent: shpeck directive in their frontmatter. This directive has no backing implementation in the project.

Changes

• pkg/tool-config/opencode.json: Removed agent: shpeck entries from all command frontmatter configurations (10 commands affected)
• test/init.integration.test.ts: Updated assertion to validate command description instead of removed directive
• test/utils/frontmatter.test.ts: Replaced test fixture reference to non-existent agent with generic example
• .gitignore: Added package-lock.json (npm artifact in Bun project)

When shpeck init --tool opencode runs, generated command files will no longer include the invalid agent directive in their YAML frontmatter.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Invalid agent directive at the top of all command files</issue_title>
<issue_description>All of the command prompt files contain agent: shpeck in the frontmatter but the project doesn't define such an agent. The line should be removed everywhere.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Invalid agent directive at the top of all command files #8

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