Add LinkedIn document posts — the swipeable PDF carousel — for both personal profiles and company pages. This is the format every major competitor exposes via native PDF upload, and the reason a trial user churned.
- New 'document' media type (application/pdf) across the upload pipeline (Type enum, HasMedia, FormRequests incl. chunked, Platform media types)
- New LinkedInDocument / LinkedInPageDocument content types: PDF-only, single-file, with a supportsDocument() flag
- Publisher flow: documents initializeUpload -> PUT -> poll AVAILABLE -> post with content.media.{id,title}; optional document_title meta (falls back to file name)
- PDF is mutually exclusive with image/video, enforced in ContentTypeCompatibleWithMedia
- Frontend: 'Document (PDF)' variant, media rules (100MB cap), composer/gallery/detail PDF cards, real PDF embed in the LinkedIn editor preview, i18n in en/es/pt-BR
- Tests: publishers (personal + page, incl. processing-failure path), enums, compatibility rule, chunked PDF upload, API + MCP document_title round-trip
LinkedIn caps documents at 100MB / 300 pages (Documents API). The page limit is enforced by LinkedIn at publish, not validated client-side.
The shared rules() returned only meta sub-keys, so every caller still repeated
its own 'platforms.*.meta' => array parent (with slightly different sometimes/
nullable combos). Fold the parent into rules() with a single safe contract so
callers just spread one source for the whole meta block.
Centralize per-platform PostPlatform.meta validation in PostPlatformMetaRules
(shared by web, REST API and MCP). The API and MCP previously only accepted
aspect_ratio, silently stripping channel_id/board_id/privacy_level and the rest
via validated(), so Discord/Pinterest/TikTok couldn't be configured or published
through those entry points. Now all per-platform meta is accepted and persisted,
required-on-publish is enforced on API update (TikTok privacy, Pinterest board,
Discord channel), and the MCP publish tool guards a post's stored meta before
dispatching. Adds API + MCP tests and a PostPlatform discord() factory state.
