feat(registry): migrate registry entries from Markdown to JSON

[amondnet]

Registry JSON Migration

Track: telemetry-driven-registry-20260413

Switch registry entries from Markdown (.md with YAML frontmatter) to JSON (.json) files in Nuxt Content v3.

Why

• Registry serves as CLI routing lookup table only — markdown body is unused
• YAML frontmatter introduces indentation pitfalls and raises contribution barrier
• JSON enables IDE autocomplete via JSON Schema and trivial validation
• Foundation for future telemetry-driven auto-registration

Scope

• Convert 50 existing .md entries to .json (automated script)
• Update content.config.ts: type: 'data', source **/*.json
• Export JSON Schema from registryEntrySchema for IDE support
• Remove dead Vue code (entry.ecosystem, entry.strategies, ContentRenderer)
• All API routes continue to work identically

Out of Scope

• Telemetry collection (separate track)
• tagPattern schema changes (separate track)
• Web UI redesign

References

• Spec: .please/docs/tracks/active/telemetry-driven-registry-20260413/spec.md
• Plan: .please/docs/tracks/active/telemetry-driven-registry-20260413/plan.md
• Ideation: .please/docs/ideas/telemetry-driven-registry.md
• Nuxt Content v3 JSON files

[amondnet]

Implementation Complete

PR #80 — Ready for Review

Summary

Registry entries migrated from Markdown (YAML frontmatter) to plain JSON files. Nuxt Content collection switched to type: 'data'. Dead Vue code removed. JSON Schema generation added for IDE autocomplete. All 53 schema tests pass, build succeeds.