v4: what the server and the client both state is declared once — several rules were written out in two or more files, some already drifting apart. A link's site name (its host without www.) was computed in five places, now shared/url.ts's siteHost; dumpFileVersion, which the frontend and the server had to keep equal by hand, is one function in shared/dump.ts; the Markdown flattening of the chat's reply previews and the digest's quotes is shared/markdown.ts's markdownToPlainText, so the digest also keeps an image's alt text; an attachment's URL and how to find one in a text are shared/attachment.ts, which the editor, Markdown and attachment-service read, its id pattern the new UUID_RE that the file and thumbnail routes check ids with. On the server, the Bandcamp, YouTube playlist and link preview caches use one TtlCache (api/lib/ttl-cache.ts) instead of three copies of the same expiry and eviction; the link previews' theme-color and the emails' theme tokens read colours with one parser (api/lib/css-color.ts), and a transparent theme-color now gives no tint; the WebSocket route sends through ws-service's send, the welcome included, so it is type-checked; fetch.ts strips an IPv6 literal's brackets with public-address's bareHostname; and a category's slug is checked by the same validateSlug as a dump's, with its own length. The migrations keep their frozen copies, as they document. 272 backend tests and 677 frontend tests pass, and deno check, tsc, eslint and doc:lint are clean.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/test/components/dump/FilePreview.test.tsx

@@ -4,11 +4,8 @@ import { userEvent } from "@testing-library/user-event";
 import { FilePreview } from "../../../components/dump/FilePreview.tsx";
 import { makeDump, makeSession } from "../../fixtures.ts";
 import { renderWithContexts } from "../../render.tsx";
-import {
-  dumpFileUrl,
-  dumpFileVersion,
-  dumpThumbnailUrl,
-} from "../../../utils/shared/urls.ts";
+import { dumpFileUrl, dumpThumbnailUrl } from "../../../utils/shared/urls.ts";
+import { dumpFileVersion } from "../../../../shared/dump.ts";
 
 describe("FilePreview", () => {
   const session = makeSession();