fix(browse): default to sonnet model to save tokens

[gregario]

Summary

• Adds model: sonnet to the /browse skill frontmatter (both template and generated SKILL.md)
• The browse skill orchestrates headless browser CLI commands — no complex reasoning required. Without an explicit model, it defaults to the user's active model (usually Opus), burning expensive tokens unnecessarily.
• Sonnet handles this equally well at a fraction of the cost, especially for multi-step flows (navigate, click, extract, repeat).

Closes #8

Test plan

• bun run gen:skill-docs --dry-run — all SKILL.md files FRESH (CI check passes)
• bun test test/skill-validation.test.ts test/gen-skill-docs.test.ts — 66/66 pass
• Manual: invoke /browse and verify it runs on Sonnet (check model in --verbose output)

🤖 Generated with Claude Code

[gregario]

Code review

No issues found. Checked for bugs and CLAUDE.md compliance.

🤖 Generated with Claude Code

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