Fix formatCard missing fields

[davegomez]

formatCard() was omitting several fields from the API response that CardSchema already supports: golden, last_active_at, image_url, and steps. MCP consumers couldn't see whether a card was golden, when it was last active, its cover image, or its checklist steps.

Now all four fields are included in the fizzy_get_card output with sensible defaults when absent (false, null, null, [] respectively). Each field has tests for both present and absent cases.

[greptile-apps]

Greptile Overview

Greptile Summary

Added four previously omitted fields (golden, last_active_at, image_url, steps) to the formatCard() output in src/tools/cards.ts:34-37. These fields were already defined in CardSchema but weren't being included in the fizzy_get_card tool response, limiting MCP consumers' visibility into card metadata.

• golden field defaults to false when absent
• last_active_at field defaults to null when absent
• image_url field defaults to null when absent
• steps array defaults to [] when absent

All four additions include comprehensive test coverage in src/tools/cards.test.ts with both present and absent scenarios (8 new test cases).

Confidence Score: 5/5

• This PR is safe to merge with no risk
• The changes are minimal, well-tested, and simply expose existing schema fields that were previously omitted. The nullish coalescing defaults are appropriate and match the schema definitions. No breaking changes or logic issues.
• No files require special attention