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.
Adds POST /api/posts/{post}/media for direct file (multipart) upload
and renames the existing URL-based flow to /api/posts/{post}/media/from-url
so the path matches HTTP semantics (POST <resource>/media expects a file
body, not JSON URLs).
The multipart action validates type against the post's enabled platforms
(image rejected on TikTok-only posts), enforces per-type size caps, and
reuses Workspace::addMedia + Post::appendMedia. URL-based attaching is
unchanged behaviorally — only the route name and controller method are
renamed for symmetry. The MCP AttachMediaFromUrlTool was already named
correctly and needs no changes; binary upload via MCP is a host-protocol
limitation that no MCP server (including Postiz) supports.
