fix(api): link digest release rows upstream, not to /release/ stubs

docs/architecture/emails.md

@@ -44,6 +44,14 @@ to break one message at a time:
   tags for the HTML part and `stripMarkdown` flattens it for the text part
   (`@releases/rendering/strip-markdown`). Escaping it verbatim shows readers
   asterisks.
+- **Release rows link upstream, not to `/release/`.** `/release/<id>` pages are
+  noindexed stubs of upstream content, so a digest's release titles and version
+  pills send the reader to the release's own `url` whenever it is http(s), the
+  same policy the web feed applies via `releaseLinkTarget()`
+  (`web/src/lib/release-link.ts`). The on-site permalink is the fallback:
+  slugged `webUrl`, then the bare-ID path, which 308s to canonical. "and N more"
+  in a rollup still goes to the product page — that's an org surface, not a
+  release stub.
 
 ## Subject lines
 

workers/api/src/lib/digest-email.ts

@@ -98,9 +98,17 @@ function digestDateLabel(cadence: "daily" | "weekly", referenceDate: string): st
   return DIGEST_DATE_FMT.format(new Date(end.getTime() - DAY_MS));
 }
 
+/**
+ * Where a release row in the digest sends the reader. Mirrors the web feed policy
+ * in `web/src/lib/release-link.ts` (`releaseLinkTarget`): `/release/<id>` pages are
+ * noindexed stubs of upstream content, so the default click goes straight to the
+ * upstream page whenever the release has a referenceable http(s) URL. The on-site
+ * permalink stays the fallback — the slugged canonical (`webUrl`, populated when the
+ * row is mapped with a webBase), then the bare-ID path, which 308s to canonical.
+ */
 function releaseUrl(baseUrl: string, r: ReleaseLatestItem): string {
-  // Prefer the slugged canonical (`webUrl`, populated when the row is mapped
-  // with a webBase); fall back to the bare-ID path, which 308s to canonical.
+  const upstream = (r.url ?? "").trim();
+  if (/^https?:\/\//i.test(upstream)) return upstream;
   return r.webUrl ?? `${baseUrl}/release/${r.id}`;
 }
 

workers/api/src/lib/email-samples.ts

@@ -216,7 +216,10 @@ function sampleDigestRelease(): ReleaseLatestItem {
     titleGenerated: null,
     titleShort: "Sample release",
     publishedAt: new Date().toISOString(),
-    url: "https://releases.sh/release/rel_sample_1",
+    // Upstream source URL — the digest's default link target (see `releaseUrl` in
+    // digest-email.ts). Kept as a third-party-looking URL so the preview is
+    // representative rather than exercising the internal-permalink fallback.
+    url: "https://example.com/changelog#sample-release",
     media: [],
     source: {
       slug: "changelog",

workers/api/test/digest-email.test.ts

@@ -49,7 +49,10 @@ describe("buildDigestEmail", () => {
     expect(subject).toContain("2");
     expect(text).toContain("ShortHeadline"); // titleShort preferred over title, matching the feed UI
     expect(text).not.toContain("RawLongTitle");
-    expect(text).toContain("https://releases.sh/release/rel_1");
+    // Release rows link upstream, not to the noindexed /release/ stub — same policy
+    // as the web feed's releaseLinkTarget().
+    expect(text).toContain("https://acme.com/changelog/1");
+    expect(text).not.toContain("https://releases.sh/release/rel_1");
     expect(text).toContain("reld_x");
     expect(html).toContain("Unsubscribe");
     expect(html).toContain("https://releases.sh/following");
@@ -63,6 +66,29 @@ describe("buildDigestEmail", () => {
     expect(html).toContain("max-width:600px");
   });
 
+  it("falls back to the on-site permalink when a release has no upstream http(s) url", () => {
+    const { text: slugged } = buildDigestEmail({
+      recipientName: "T",
+      cadence: "daily",
+      releases: [rel({ url: null, webUrl: "https://releases.sh/release/rel_1-thing" })],
+      baseUrl: "https://releases.sh",
+      manageUrl: "https://releases.sh/following",
+      unsubscribeUrl: "https://api.releases.sh/v1/digest/unsubscribe/reld_x",
+    });
+    expect(slugged).toContain("https://releases.sh/release/rel_1-thing");
+
+    // No webUrl either → the bare-ID path, which 308s to canonical.
+    const { text: bare } = buildDigestEmail({
+      recipientName: "T",
+      cadence: "daily",
+      releases: [rel({ url: null })],
+      baseUrl: "https://releases.sh",
+      manageUrl: "https://releases.sh/following",
+      unsubscribeUrl: "https://api.releases.sh/v1/digest/unsubscribe/reld_x",
+    });
+    expect(bare).toContain("https://releases.sh/release/rel_1");
+  });
+
   it("compresses a per-product version burst to the newest release + notes", () => {
     const ghSource = {
       slug: "sdk",
@@ -103,7 +129,7 @@ describe("buildDigestEmail", () => {
     expect(text).toContain("Latest — Fixed a socket leak");
     // "and N more" links to the product page; the pill itself links to the release.
     expect(text).toContain("https://releases.sh/acme/widget");
-    expect(html).toContain('href="https://releases.sh/release/t1"');
+    expect(html).toContain('href="https://acme.com/changelog/1"');
     expect(html).toContain(">4.2.1</a>");
     expect(html).toContain("and 1 more");
     expect(html).toContain("&middot; 2 releases");