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/application/email-processor.ts

@@ -1,7 +1,7 @@
 import { EmailParser } from "../domain/email-parser";
 import { AttachmentData, EmailMetadata, Env } from "../types";
 import { bumpCounters } from "../application/stats";
-import { applyFeedEvents } from "../application/feed-events";
+import { dispatchFeedEvents } from "../application/feed-events";
 import { extractEmailDomain } from "../infrastructure/favicon-fetcher";
 import { parseOneClickUnsubscribe } from "../infrastructure/unsubscribe";
 import { getAttachmentBucket } from "../infrastructure/attachments";
@@ -188,7 +188,7 @@ async function storeEmail(
   const schedule: BackgroundScheduler = ctx
     ? (p) => ctx.waitUntil(p)
     : () => {};
-  await applyFeedEvents(feed.id, feed.pullEvents(), env, schedule);
+  await dispatchFeedEvents(feed, env, schedule);
 }
 
 export async function processEmail(