ParsedAttachment.DisplayURL() returned the preview URL
(preview.3.basecamp.com/.../previews/full) before the download href
(storage.3.basecamp.com/.../download/<filename>). For non-image
attachments (csv, xlsx, zip, pdf, ...) the preview endpoint returns a
generic SVG file-type icon, so every caller that went through
DisplayURL() downloaded a ~3.8KB placeholder instead of the real file.
Image attachments happened to work because their preview URL returns
the real image, which is why this bug went unnoticed.

Every internal caller of DisplayURL() is a download path (cards show
--download-attachments, attachments list, attachments download,
downloadableAttachments), so preferring Href is correct across the
board. URL is kept as a fallback for the rare case where an attachment
has no downloadable blob.

The existing richtext unit test pinned the wrong behavior ("URL wins")
and the commands TestAttachmentMeta fixture did the same; both are
updated to assert the new contract with a non-image-looking URL pair.

The generic /recordings/<id>.json endpoint is not addressable at the
account scope for every recording type. Kanban::Card is the concrete
case: its recording is only reachable via the bucket-scoped
/buckets/<bucket>/card_tables/cards/<id>.json endpoint, so the generic
lookup returns 404. Before this commit, fetchItemContent routed that
404 through convertSDKError and surfaced a bare "Resource not found"
error, leaving the user with no hint that --type was required.

The existing 204 branch of the same function already emits a friendly
"Specify a type" usage hint listing every accepted type. Do the same
on 404 from the generic path so cards (and any other bucket-scoped
type) produce the actionable error. Narrow scope: only fires when
isGenericType(recordType) and the SDK error is CodeNotFound, so any
path that already worked is untouched.

Pulls the hint string into a package const (genericLookupTypeHint) so
the 204 and 404 branches stay in sync.

Trix (the editor behind Basecamp's rich-text fields) stores paragraphs as
<div>...</div> and blank-line separators as <div><br></div>. goldmark's
default output — <p>...</p>\n<br>\n<p>...</p> — renders with the block
margins of <p> *plus* the line break of the intervening <br>, producing
double spacing in Basecamp between what the user typed as a single blank
line between two paragraphs.

MarkdownToHTML changes:
- trixRenderer registers renderParagraph, emitting <div>...</div> for
  top-level paragraphs. trixTransformer already converts paragraphs
  inside lists and blockquotes into TextBlocks, so this only fires where
  it should.
- trixRenderer.renderTrixBreak emits <div><br></div>\n instead of <br>\n.
- trixRenderer.renderHTMLBlock wraps raw HTML blocks in <div> instead of
  <p> for consistency.
- The MarkdownToHTML error-path fallback ("<p>" + escaped + "</p>")
  mirrors the new shape.

HTMLToMarkdown changes (for round-trip fidelity with Trix-native HTML
coming from the API):
- Add reDivBr and reDiv patterns running before the existing <p>/<br>
  pipeline: <div><br></div> becomes a blank line, <div>...</div> becomes
  a paragraph.
- blockquoteInnerToMarkdown gains <div>/<div><br></div> handling so
  multi-paragraph blockquotes round-trip cleanly; without it, the inner
  <div><br></div> cascades through the outer blockquote line-splitter
  and produces extra ">" lines.

Test updates:
- MarkdownToHTML expected strings flip <p>→<div>, </p>→</div>, and the
  block-level break \n<br>\n → \n<div><br></div>\n. Applied via a
  targeted sweep, verified one by one against the rendered output.
- ResolveMentions test inputs flip <p>→<div> to stay representative of
  what MarkdownToHTML now produces and what Trix emits natively.
- TestEditLoopRoundTrip/multi-paragraph_blockquote: now passes cleanly
  because of the new blockquote <div> handling.
- TestCheckinsAnswerCreateDefaultsDateToToday in internal/commands
  asserted the wrapper shape; updated to <div>.

Inline <br> inside a paragraph (consecutive lines with single \n between
them) is unchanged: trixTransformer still converts soft-break → hard-break
inside <div>, matching Trix's own line-break representation.

Combines both PRs' branches for local use via `go install`:
- PR #421 (trix): <div>/<div><br></div> paragraph shape, soft→hard break
  in top-level paragraphs, HTMLToMarkdown round-trip for <div>.
- PR #447 (attachments): prefer download Href over preview URL in
  ParsedAttachment.DisplayURL; suggest --type on 404 from generic
  /recordings lookup.

Upstream each PR remains separately reviewable at basecamp/basecamp-cli.

Adds 'basecamp chat update <id|url> [content]' for editing existing
campfire lines in place via PUT /chats/{c}/lines/{l}. Mirrors 'chat post'
shape: positional content or --content flag, --content-type for HTML,
@mention resolution with auto-promotion to text/html.

Backed by basecamp-sdk CampfiresService.UpdateLine. While the SDK
addition is in flight, go.mod has a temporary replace pinning to a
fork branch carrying just that operation; the replace is dropped
once an SDK release with UpdateLine ships.

Wires up surface snapshot, smoke + e2e coverage, and the basecamp
skill documentation.

Addresses Copilot review on basecamp/basecamp-sdk#295: align UpdateLineOptions
ContentType doc with the rest of the campfires service (API defaults to plain
text).

Adds 'basecamp chat update <id|url> [content]' for editing existing
campfire lines in place via PUT /chats/{c}/lines/{l}. Mirrors 'chat post'
shape: positional content or --content flag, --content-type for HTML,
@mention resolution with auto-promotion to text/html.

Backed by basecamp-sdk CampfiresService.UpdateLine. While the SDK
addition is in flight, go.mod has a temporary replace pinning to a
fork branch carrying just that operation; the replace is dropped
once an SDK release with UpdateLine ships.

Wires up surface snapshot, smoke + e2e coverage, and the basecamp
skill documentation.

…d assertion

Adds 'basecamp chat update <id|url> [content]' for editing existing
campfire lines in place via PUT /chats/{c}/lines/{l}. Mirrors 'chat post'
shape: positional content or --content flag, --content-type for HTML,
@mention resolution with auto-promotion to text/html.

Backed by basecamp-sdk CampfiresService.UpdateLine. While the SDK
addition is in flight, go.mod has a temporary replace pinning to a
fork branch carrying just that operation; the replace is dropped
once an SDK release with UpdateLine ships.

Wires up surface snapshot, smoke + e2e coverage, and the basecamp
skill documentation.

…ance

Adds 'basecamp chat update <id|url> [content]' for editing existing
campfire lines in place via PUT /chats/{c}/lines/{l}. Mirrors 'chat post'
shape: positional content or --content flag, --content-type for HTML,
@mention resolution with auto-promotion to text/html.

Backed by basecamp-sdk CampfiresService.UpdateLine. While the SDK
addition is in flight, go.mod has a temporary replace pinning to a
fork branch carrying just that operation; the replace is dropped
once an SDK release with UpdateLine ships.

Wires up surface snapshot, smoke + e2e coverage, and the basecamp
skill documentation.

# Conflicts:
#	internal/commands/chat.go