feat(skills): improve documentation research and workflow setup

[Max17190]

Why

Official documentation questions should get version-aware guidance through the existing developer-index skill, and the CLI needs to install the two new workflow skills. This resubmits #318, reverted in #319, with one correction.

Summary

• Same scope as feat(skills): improve documentation research and workflow setup #318: an on-demand official documentation reference for firecrawl-developer-index, guidance that distinguishes a merged fix from released behavior and names the release check (release notes, changelog entry or tag), firecrawl-job-postings and firecrawl-fantasy-sports registered in the workflow selection (18 workflows), and the init and setup tests.
• Developer-index description rewritten to load the skill when model knowledge is likely stale: the user names a version, is upgrading, pastes an error from a library or tool, or asks how to use, configure or migrate a specific library or API, and whenever a version, option, error or API is unfamiliar. It also states what the skill is not for (general concepts, code that uses no specific library, refactoring supplied code). The reuse guidance stays in the reference body.
• Version 1.26.8; 1.26.6 and 1.26.7 are already published.
• Merge only after feat(skills): enhance existing CLI workflows firecrawl-workflows#11 is merged and its catalog sync has added both new workflows to firecrawl/skills. Until then, firecrawl setup job-postings and firecrawl setup fantasy-sports exit with an error because the catalog does not have those names, and firecrawl setup workflows installs the other 16 workflows without them.

Test Plan

• pnpm run build, pnpm run type-check, pnpm run format:check
• pnpm test: 38 files and 689 tests passed with FIRECRAWL_API_KEY unset
• Agent eval with the CLI skills installed: the new description makes agents look up current documentation for questions about recent releases, with no lookups on prompts that need none
• The built CLI reports 1.26.8 and lists 18 workflow skills, including the two new ones
• Every command and flag in the developer-index skill and its reference checked against the built CLI's --help; firecrawl developer and firecrawl search --categories developer --sources web run against production
• Installed firecrawl-developer-index from this branch into an isolated project with the standard skills installer; the reference file is packaged

[cubic-dev-ai]

All reported issues were addressed across 6 files

<sub>Shadow auto-approve: would not auto-approve because issues were found.

View guided diff | Turn on auto-fix | Re-trigger cubic</sub>

[cubic-dev-ai]

0 issues found across 1 file (changes from recent commits).

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

<sub>Shadow auto-approve: would require human review. Adds an official-docs reference to the developer-index skill and registers two new workflow skills, with tests and a version bump. Merge safety depends on an external catalog sync not visible in the diff; the installer silently skips missing skills.

View guided diff | Turn on auto-fix | Re-trigger cubic</sub>

[cubic-dev-ai]

0 issues found across 1 file (changes from recent commits).

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

<sub>Shadow auto-approve: would require human review. Adds an official-docs reference to the developer-index skill, registers two workflow skills in the CLI installer, adds tests, and bumps the version. Merge safety depends on an external catalog sync (firecrawl/firecrawl-workflows#11) that is not visible in this diff.

View guided diff | Turn on auto-fix | Re-trigger cubic</sub>