refactor: split src into domain / application / infrastructure layers

Replace the history-driven lib/ + utils/ split with DDD layers:
- domain/: aggregate, repositories, value objects, pure parsers/format
- application/: feed-service, email-processor, feed-fetcher, stats
- infrastructure/: logging, auth, KV/R2 adapters, HTTP, framework glue

Pure file relocation; imports updated mechanically. Behaviour unchanged.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/infrastructure/feed-generator.ts

@@ -0,0 +1,114 @@
+import { Feed } from "feed";
+import { FeedConfig, EmailData } from "../types";
+import { processEmailContent } from "./html-processor";
+
+export { processEmailContent as extractBodyContent };
+
+function parseFromAddress(from: string): { name: string; email?: string } {
+  const match = from.match(/^(.*?)\s*<([^>]+)>\s*$/);
+  if (match) {
+    return { name: match[1].trim() || match[2], email: match[2].trim() };
+  }
+  const emailOnly = from.match(/^[^\s@]+@[^\s@]+\.[^\s@]+$/);
+  if (emailOnly) {
+    return { email: from.trim(), name: from.trim() };
+  }
+  return { name: from.trim() };
+}
+
+function buildFeed(
+  feedConfig: FeedConfig,
+  emails: EmailData[],
+  baseUrl: string,
+  feedId: string,
+  selfUrl?: { rss?: string; atom?: string },
+): Feed {
+  const iconUrl = `${baseUrl}/favicon/${feedId}`;
+  const feed = new Feed({
+    title: feedConfig.title,
+    description: feedConfig.description || "",
+    // Per-feed icon derived from the last sender's domain (self-falls-back to
+    // the project icon). image → RSS <image>/Atom <logo>; favicon → Atom <icon>.
+    image: iconUrl,
+    favicon: iconUrl,
+    // Computed dynamically so the id is always canonical regardless of what
+    // was stored in KV at feed-creation time (which may have used a stale domain).
+    id: `${baseUrl}/rss/${feedId}`,
+    // Link points to the admin emails page — the "website" this feed represents.
+    link: `${baseUrl}/admin/feeds/${feedId}/emails`,
+    language: feedConfig.language,
+    updated: new Date(),
+    generator: "kill-the-news",
+    copyright: `Copyright © ${new Date().getFullYear()} ${feedConfig.title}`,
+    feedLinks: {
+      rss: selfUrl?.rss ?? `${baseUrl}/rss/${feedId}`,
+      atom: selfUrl?.atom ?? `${baseUrl}/atom/${feedId}`,
+    },
+    author: feedConfig.author
+      ? {
+          name: feedConfig.author,
+          email: `noreply@${new URL(baseUrl).hostname}`,
+        }
+      : undefined,
+  });
+
+  for (const email of emails) {
+    const entryUrl = `${baseUrl}/entries/${feedId}/${email.receivedAt}`;
+    const firstAttachment = email.attachments?.[0];
+    const bodyContent = processEmailContent(
+      email.content,
+      email.attachments,
+      baseUrl,
+    );
+    feed.addItem({
+      title: email.subject,
+      id: entryUrl,
+      link: entryUrl,
+      description: bodyContent,
+      content: bodyContent,
+      author: [parseFromAddress(email.from)],
+      date: new Date(email.receivedAt),
+      enclosure: firstAttachment
+        ? {
+            url: `${baseUrl}/files/${firstAttachment.id}/${encodeURIComponent(firstAttachment.filename)}`,
+            type: firstAttachment.contentType,
+            length: firstAttachment.size,
+          }
+        : undefined,
+    });
+  }
+
+  return feed;
+}
+
+export function generateRssFeed(
+  feedConfig: FeedConfig,
+  emails: EmailData[],
+  baseUrl: string,
+  feedId: string,
+  selfUrl?: string,
+): string {
+  return buildFeed(
+    feedConfig,
+    emails,
+    baseUrl,
+    feedId,
+    selfUrl ? { rss: selfUrl } : undefined,
+  ).rss2();
+}
+
+export function generateAtomFeed(
+  feedConfig: FeedConfig,
+  emails: EmailData[],
+  baseUrl: string,
+  feedId: string,
+  selfUrl?: string,
+): string {
+  return buildFeed(
+    feedConfig,
+    emails,
+    baseUrl,
+    feedId,
+    selfUrl ? { atom: selfUrl } : undefined,
+  ).atom1();
+}