Turn the image library into a file library, with a per-blog upload limit

Bloggers want to attach PDFs, archives, audio and other files to posts,
not only images. The Images tab becomes Files: any type is accepted,
listed by kind with search, paging, rename and multi-file upload, and the
editor's paste/drop/"Insert file" takes anything (images are shown,
everything else becomes a link). The default limit goes from 5 to 10 MB
and the superadmin can override it per blog from /admin/.

Files stay in Postgres so one pg_dump is still the whole blog. The bytea
column is STORAGE EXTERNAL and /media streams it in substring() slices,
so serving never holds a whole file in memory whatever limit a blog gets.

Serving any type on the root domain, which carries the session cookie,
needs a policy: uploads are typed by sniffing (the extension may only
refine a generic sniff to an allowlisted type) and only images, PDF,
plain text, audio and video render inline; HTML, SVG, XML, scripts,
archives and binaries always go out as application/octet-stream with
Content-Disposition: attachment.

The body cap moves out of requireAuth into guardPOST, which runs after
withBlog has resolved the blog and so knows its limit.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Sd8UPWrvyYCLj97JexNw3A

1 files changed, 3 insertions, 3 deletions

diff --git a/internal/web/handlers_sections.go b/internal/web/handlers_sections.go
index 325192e..eb45e1c 100644
--- a/internal/web/handlers_sections.go
+++ b/internal/web/handlers_sections.go
@@ -73,10 +73,10 @@ func (s *Server) handleSectionSave(w http.ResponseWriter, r *http.Request) {
 	fail := func(msg string) {
 		s.renderStatus(w, r, http.StatusBadRequest, "dashboard/section_form.html", map[string]any{"section": sec, "error": msg})
 	}
-	img, err := s.readUpload(r, "inline_image")
+	img, err := s.readUpload(r, "inline_file", false)
 	switch {
 	case err != nil:
-		fail(s.tr(r, "Image not added:") + " " + err.Error())
+		fail(s.tr(r, "File not added:") + " " + err.Error())
 		return
 	case len(sec.Title) > 120:
 		fail(s.tr(r, "Title is too long (max 120 characters)."))
@@ -88,7 +88,7 @@ func (s *Server) handleSectionSave(w http.ResponseWriter, r *http.Request) {
 		fail(s.tr(r, "Announcement is too long (20 KB max)."))
 		return
 	}
-	sec.BodyMD = appendImageMD(sec.BodyMD, img)
+	sec.BodyMD = appendFileMD(sec.BodyMD, img)
 	sec.BodyHTML = markdown.Render(sec.BodyMD)
 	if sec.ID == 0 {
 		sec, err = blogStore(r).CreateSection(r.Context(), sec)