CLI gen: default human-readable response formatter with --json toggle

[HavenDV]

Part of #338.

Today

Every generated command calls CliRuntime.WriteJsonAsync(...) — raw JSON is the only output. Users who want a readable terminal view (let alone scrubbing structured data into a pipeline) have to write custom formatters per response type.

Firecrawl's Commands/ ships FormatScrapeResponse, FormatCrawlStatus, FormatStartResult, etc. — hundreds of lines of hand-written formatting. The pattern is uniform: walk the response, highlight key scalars, render arrays as bullets, render dates with a sensible format.

Target

Default to a generic schema-walking formatter; opt out to raw JSON with --json.

$ firecrawl scrape https://example.com
URL:         https://example.com
Status:      success
Markdown:    # Example Domain ...
Metadata:
  - title:       Example Domain
  - language:    en
  - statusCode:  200

$ firecrawl scrape https://example.com --json
{"url":"...","markdown":"...",...}

Proposed approach

1. Generate a Format<TResponse>(TResponse value) method per response type that walks the model's PropertyData:
   • scalar → key: value line
   • string > 80 chars → truncate with ellipsis (full text behind --json or --output file.txt)
   • array of scalar → multi-line bullets
   • nested object → indented sub-section
   • array of object → numbered entries with two-level indent
   • dates → yyyy-MM-dd HH:mm:ss UTC
2. --json recursive option at the root command level (added to existing --api-key/--base-url set) flips output mode. Already half-present: CliRuntime.WriteJsonAsync exists; needs a sibling WriteFormattedAsync.
3. Vendor extension x-cli-format on a property:
   • key → render at the top of the output
   • hidden → skip from formatted view (still in --json)
   • code → render in a code-block style (preformatted)
4. Partial-class hook for full override:

   partial class ScrapeCommand
   {
       static partial Task<string> CustomizeFormatAsync(Response response, ParseResult ctx);
   }

5. Mirror to CliGenerator.cs.

Acceptance criteria

• Default firecrawl scrape <url> shows human-readable output, --json shows raw JSON.
• x-cli-format: key on a property promotes it to the top of the output.
• Partial-class override works without touching the generated .g.cs file.
• Snapshot tests cover at least: simple scalar response, nested object, array of objects, mixed.