refactor(sanity): clean up schemas, organize Studio structure, and optimize GROQ queries

[codercatdev]

Summary

• Sanity Schema Cleanup (apps/sanity/schemas/):
  • Removed 20 retired AI/video engine, legacy preview, and unqueried content schemas (engineConfig, contentConfig, dashboardSettings, gcsConfig, pipelineConfig, remotionConfig, sponsorConfig, automatedVideo, contentIdea, mediaAsset, videoAnalytics, sponsorLead, sponsorPool, previewSession, sponsorshipRequest, sharePreviewAction, course, lesson, short, podcastSeries, category, and socialPreviewFields).
  • Removed unused fields on podcast, post, page, sponsor, guest, and content, and made podcastType optional/hidden when unset since there is only one active podcast.
  • Restricted transcript.contentRef and sync-missing-youtube-transcripts to ["post", "podcast", "page"].
• Sanity Studio Structure Refactor (apps/sanity/structure.ts):
  • Organized Studio into a clean Editorial Hub (Site Settings, Publishing & Release Readiness including drafts.** and Content Releases versions.**, Posts, Podcasts without "By Type" nesting, Pages, People & Sponsors, and Automation & Intelligence) with zero duplicate root items.
  • Updated @sanity/assist presets (apps/sanity/plugins/assist.ts) with CodingCat.dev-specific instructions for both post and podcast.
• GROQ Query & Reference Optimizations (apps/site/src/lib/sanity/queries/):
  • Replaced array membership scans (^._id in author[]._ref || ^._id in guest[]._ref) in userRelated and sponsorRelated with Sanity's indexed references(^._id) filter.
  • Replaced ... in author[]->, guest[]->, sponsor[]->, and pick[].user-> with lean personRefFields and sponsorRefFields projections.
  • Separated portableTextFields from contentFields for people.ts and sponsors.ts.
  • Removed the non-optimizable transcript->statistics.viewCount join in homePageQuery filters and order(), sorting directly on statistics.youtube.viewCount.
• Sanity MCP & Editorial Workflow Skill:
  • Fixed field projections and schema definitions in apps/site/src/pages/api/mcp.ts.
  • Added .agents/skills/sanity-editorial-workflow/SKILL.md for Sanity MCP + CLI content releases readiness, Gemini drafting, and cover photo generation/upload.

Verification

• pnpm typegen (regenerated apps/sanity/extract.json and apps/site/src/lib/sanity/types.gen.ts)
• pnpm lint (0 errors)
• pnpm typecheck (0 errors, 0 warnings)
• pnpm build & pnpm build:studio

[github-actions]

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