fix(blog): rich-text toolbar + inline link editor, and VTEX product picker

[aka-sacci-ccr]

Blog CMS fixes, split across two commits.

1. Rich-text toolbar + inline link editor (fix)

The paragraph TipTap editor's formatting toolbar (bold/italic/underline/link) only appeared on keyboard interaction, not on mouse selection, and the link flow used a native window.prompt.

• TipTap v3 no longer re-renders on transactions by default, so reading editor.isFocused/isActive() during render went stale — the toolbar never showed on mouse selection and mark highlights lagged. Now selected reactively via useEditorState.
• Replaced the native window.prompt link dialog with an inline, Figma-like popover (Enter to apply, Esc to cancel, remove-link button). Extracted the shared ToolbarButton + new RichTextLinkControl, added normalizeLinkUrl (bare domains → https), and validated blog links with isSafeLinkUrl (previously unchecked).

2. VTEX product picker for ProductShelf/ProductCard (feat)

The shelf/card editors only accepted raw SKU ids typed by hand.

• Added a Browse products dialog (VTEX-only for now, mirroring the preview path-param picker) to discover products by free search, category, or collection/cluster id — invoking vtex/loaders/intelligentSearch/productList.ts through the mesh preview-invoke proxy.
• Toggling a product writes its SKU id via the existing writeProductListIds, so the section still receives Product[] and storage is unchanged.
• Threaded the sandbox ref (org/vm/branch) from Post/Category editors → BlockDocument → BlockRow → BlockEditor so blocks can invoke loaders. The picker only shows when a running sandbox is available; manual id entry remains the fallback.

Testing

• bun test on the new pure logic (link normalization/validation, picker request-builders + payload mappers) — passing.
• bun run fmt, oxlint, and workspace typecheck clean.
• Picker exercised end-to-end against a running VTEX sandbox (search/category/cluster return real products; selected ids persist).

Note: the storefront-side rendering of the shelf (resolving ids → products on the site's blog route) lives in the site repo, not here — this PR is the CMS/editor side only.

🤖 Generated with Claude Code

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Summary by cubic

Fixes the blog rich-text toolbar and link flow (now with a same-tab/new-tab toggle), adds a VTEX product picker with rich product cards, adds a heading level selector for ProductShelf titles, and flags incomplete posts to block preview until required fields are filled.

• New Features

  • Product picker dialog: search by name/ID, browse by category, or by collection/cluster — invokes vtex/loaders/intelligentSearch/productList.ts and vtex/loaders/categories/tree.ts via the mesh preview-invoke proxy. Shows only with a running sandbox; manual ID input remains the fallback. Shelf shows a sortable product grid (drag to reorder, hover to remove) and ProductCard shows a compact selected-product row; still persists SKU IDs only via a new useProductsByIds lookup.
  • ProductShelf title: choose Normal/H1/H2/H3; the level is stored inline (e.g. <h1>Title</h1>) and the editor previews the size.
  • Post validation: highlight missing fields (Title, Slug, Category, Excerpt, Cover image) in the list and editor, show an issues badge, and disable “See preview” until fixed.

• Bug Fixes

  • Rich-text toolbar now selects state via useEditorState, so it appears on mouse selection and mark highlights stay in sync.
  • Replaced the window.prompt link flow with an inline popover (Enter to apply, Esc to cancel, remove link) and added a same-tab/new-tab toggle that sets target (and rel for new-tab). Cleared TipTap’s default link HTMLAttributes so each link’s target controls behavior. Added normalizeLinkUrl and validated URLs with isSafeLinkUrl.
  • Removed unused REQUIRED_POST_FIELDS export.

^{Written for commit 8acbdef. Summary will update on new commits.}