Add browse.sh browser skill Markdown catalog

[shrey150]

Add a top-level browser-skills/ collection alongside skills/, containing all 467 entries returned by the public browse.sh catalog on 2026-09-09: 467 SKILL.md files and 36 supporting Markdown files. No scripts, binaries, screenshots, or archives are imported.

455 entries were downloaded through /api/skills/<domain>/<task>/files. The remaining 12 catalog entries return 404 from that endpoint and point to existing public browserbase/skills directories; their Markdown was downloaded from those source paths at commit 6811ca3.

Skill bodies and upstream status/metadata are retained. Names are namespaced by hostname and task to avoid collisions across sites and with existing skills; trailing whitespace is removed. The catalog README maps every exported name to its public source. Script-backed snapshots still require their full upstream distribution, as documented in that README.

The existing marketplace manifest now explicitly declares the new skill paths. Vercel's default discovery finds skills/ first and otherwise skips a sibling folder. The repository validator now checks snapshot names, descriptions, Markdown-only contents, index links, and manifest coverage while preserving the existing authored-skill checks.

The skills.sh namespace remains browserbase/skills, with individual skill names below it. A browser-skills folder does not create a browserbase/browser-skills repository route. Verified against Vercel's discovery source, manifest support, installation telemetry, and the directory FAQ. Listing depends on install telemetry; opening this draft does not publish directory entries.

Validation:

• node scripts/validate-skills.mjs: 18 existing skills and all 467 snapshots pass; one existing authored-skill warning.
• Executed Vercel's discoverSkills from the pinned source: 485 total skills, including all 467 browser skills, with no duplicate names. Direct folder discovery also returns all 467.
• Export manifest: all 503 expected Markdown paths present; downloaded source hashes retained in the local audit records.
• node --check scripts/validate-skills.mjs and git diff --check pass.

This is a visibility/export change. The 467 skill workflows have not been executed or re-certified, and their original public endpoint details and upstream metadata remain part of the snapshots.