refactor: separate Feed domain state from persistence DTO

Move four DDD tensions on the Feed aggregate to ground:

- #1 The aggregate now holds a domain FeedState (camelCase) instead of the
  snake_case FeedConfig DTO; infrastructure/feed-mapper.ts owns the
  FeedState<->FeedConfig/FeedListItem translation as the sole snake_case site
  outside the HTTP edge.
- #3 Replace the edit() recomputeExpiry control flag with a Lifetime VO:
  passing a lifetime recomputes expiry, omitting it preserves the current one
  (the dashboard quick-edit path).
- #4 Domain events carry their own feedId; dispatchFeedEvents centralizes the
  drain+dispatch in the application layer (no more manual pullEvents at call
  sites), keeping infra->application dependency direction intact.
- #6 Rename FeedId.fromTrusted to FeedId.unchecked to make the absence of
  revalidation explicit.

Adds Lifetime + feed-mapper round-trip tests. 353 tests green, tsc clean,
wrangler dry-run OK. Docs (CLAUDE.md) synced.

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

src/infrastructure/feed-repository.test.ts

@@ -6,7 +6,7 @@ import { FeedId } from "../domain/value-objects/feed-id";
 import type { Env, FeedConfig, FeedMetadata, EmailData } from "../types";
 
 const mockEnv = () => createMockEnv() as unknown as Env;
-const fid = (value: string) => FeedId.fromTrusted(value);
+const fid = (value: string) => FeedId.unchecked(value);
 
 const sampleConfig = (overrides: Partial<FeedConfig> = {}): FeedConfig => ({
   title: "Test Feed",
@@ -106,9 +106,11 @@ describe("FeedRepository feed list", () => {
       {
         title,
         language: "en",
-        created_at: 1000,
+        allowedSenders: [],
+        blockedSenders: [],
+        createdAt: 1000,
         description: opts.description,
-        expires_at: opts.expires_at,
+        expiresAt: opts.expires_at,
       },
       { emails: [] },
     );