refactor(domain): add FeedId, EmailAddress and Domain value objects

Encapsulate the email/domain/feed-id parsing that was scattered as ad-hoc
regexes and split("@") calls into three small immutable value objects under
src/domain/value-objects/. EmailParser.extractFeedId and generateFeedId now
delegate to FeedId; the sender policy, favicon domain extraction and the admin
SenderField parse through EmailAddress/Domain.

Left as-is on purpose: forwardemail's multi-address free-text extraction and the
admin allow/block list normaliser, which operate on mixed email-or-domain input
that the single-address value objects would reject.

Behaviour-preserving; adds unit tests for each value object.

Co-Authored-By: Claude Opus 4.7 <[email protected]>

src/utils/email-parser.ts

@@ -1,10 +1,10 @@
 import { EmailData } from "../types";
+import { FeedId } from "../domain/value-objects/feed-id";
 
 export class EmailParser {
   // Matches noun1.noun2.XY (the feed ID format) before the @ symbol
   static extractFeedId(emailAddress: string): string | null {
-    const match = emailAddress.match(/^([a-z]+\.[a-z]+\.\d{2})@/i);
-    return match ? match[1] : null;
+    return FeedId.parse(emailAddress)?.value ?? null;
   }
 
   // eslint-disable-next-line @typescript-eslint/no-explicit-any

src/utils/favicon-fetcher.ts

@@ -5,6 +5,7 @@ import {
   MAX_ICON_BYTES,
 } from "../config/constants";
 import { FeedRepository } from "../domain/feed-repository";
+import { EmailAddress } from "../domain/value-objects/email-address";
 import { logger } from "../lib/logger";
 
 interface IconRecord {
@@ -18,10 +19,7 @@ interface IconRecord {
  * no plausible address can be parsed.
  */
 export function extractEmailDomain(from: string): string | null {
-  const match = from.match(/[^\s<>@]+@([^\s<>@]+\.[^\s<>@]+)/);
-  if (!match) return null;
-  const domain = match[1].trim().toLowerCase().replace(/\.+$/, "");
-  return domain || null;
+  return EmailAddress.parse(from)?.domain.value ?? null;
 }
 
 function arrayBufferToBase64(buffer: ArrayBuffer): string {

src/utils/id-generator.ts

@@ -1,17 +1,9 @@
-import { nouns } from "../data/nouns";
+import { FeedId } from "../domain/value-objects/feed-id";
 
 /**
  * Generates a random feed ID in the format noun1.noun2.XY
  * @returns A random feed ID string
  */
 export function generateFeedId(): string {
-  // Select two random nouns
-  const noun1 = nouns[Math.floor(Math.random() * nouns.length)];
-  const noun2 = nouns[Math.floor(Math.random() * nouns.length)];
-
-  // Generate a random 2-digit number between 10 and 99
-  const number = Math.floor(Math.random() * 90) + 10;
-
-  // Combine to create the ID with dots as separators
-  return `${noun1}.${noun2}.${number}`;
+  return FeedId.generate().value;
 }