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/routes/admin/emails.tsx

@@ -1,6 +1,6 @@
 import { Hono } from "hono";
 import { Env, EmailMetadata } from "../../types";
-import { logger } from "../../lib/logger";
+import { logger } from "../../infrastructure/logger";
 import { Layout, clampText } from "./ui";
 import {
   deleteAttachmentsForEmails,
@@ -8,8 +8,12 @@ import {
 } from "./helpers";
 import { FeedRepository } from "../../domain/feed-repository";
 import { FeedId } from "../../domain/value-objects/feed-id";
-import { feedRssUrl, feedAtomUrl, feedEmailAddress } from "../../utils/urls";
-import { formatBytes } from "../../utils/format";
+import {
+  feedRssUrl,
+  feedAtomUrl,
+  feedEmailAddress,
+} from "../../infrastructure/urls";
+import { formatBytes } from "../../domain/format";
 import { EmailAddress } from "../../domain/value-objects/email-address";
 import { emailsPageScript } from "../../scripts/generated/emails-page";