fix(cms): list and edit Tanstack installed apps in Content tab

[guitavano]

Summary

• App catalog: merge installed apps from store, manifest.blocks.apps, and decofile scan (custom/local apps) without a manifestHasApp gate.
• Schema resolution: use btoa instead of Buffer for base64 defs lookup (fixes Buffer is not defined in the browser); support legacy resolveType aliases via isDecoAppResolveType.
• Page list: find site app entries with isSiteAppBlock and allow app extraction when resolve type matches without requiring manifest presence.

Part of the Tanstack CMS apps stack alongside:

• deco-start feat(schema): generate app JSON Schemas from src/apps blocks#257
• apps-start feat(cms): export Props for VTEX, blog, and website cms-props apps-start#79
• baggagio-tanstack https://github.com/deco-sites/bagaggio-tanstack/pull/141

Test plan

• bun test apps/mesh/src/web/components/sandbox/content/app-catalog.test.ts apps/mesh/src/web/components/sections-editor/resolve-schema.test.ts
• Open baggagio sandbox → Content → Apps tab lists VTEX, site, blog, etc.
• Edit app props in Studio without browser crash on schema lookup

Made with Cursor

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Summary by cubic

CMS Content → Apps now lists and lets you edit installed Tanstack apps, including custom/local ones, even when missing from manifest.blocks.apps. Adds secret field support and drag‑to‑reorder for array fields in app forms, with safer, browser‑friendly schema resolution.

• New Features

  • Merge app catalog from store, manifest.blocks.apps, and decofile (no gate).
  • Detect and include custom/local apps via block key or resolveType; label as “Custom” or “Installed”.
  • Render website/loaders/secret.ts blocks as password fields and keep existing secrets unless a new value is set.
  • Enable drag‑to‑reorder on schema array fields; prevent item open while dragging.
  • Improve app and array item labels using appLabel and support {{...}} titles via titleBy.

• Bug Fixes

  • Use btoa base64 lookup for schema definitions to avoid Buffer is not defined in the browser.
  • Resolve app schemas via base64 keys and legacy resolveType aliases for Tanstack sites, including when only in global schema definitions.

^{Written for commit 1470389. Summary will update on new commits.}