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/domain/events.ts

@@ -1,9 +1,11 @@
+import { FeedId } from "./value-objects/feed-id";
+
 /**
  * Domain events the Feed aggregate records when it mutates. They describe *what
- * happened* in business terms; the application layer decides which side effects
- * to run (counters, WebSub pings, favicon caching) via a dispatcher. This keeps
- * the aggregate ignorant of infrastructure and the orchestration code free of
- * scattered, inline side effects.
+ * happened* in business terms and carry their own `feedId`, so the application
+ * dispatcher can route side effects (counters, WebSub pings, favicon caching)
+ * without the caller threading the id back in. This keeps the aggregate ignorant
+ * of infrastructure and the orchestration code free of scattered, inline effects.
  *
  * Only mutations that currently have side effects emit events — feed creation
  * and email ingestion. Edits and removals carry no side effect, so they emit
@@ -12,5 +14,5 @@
  * outside this mechanism by design — they have no aggregate event to ride on.
  */
 export type FeedEvent =
-  | { type: "FeedCreated" }
-  | { type: "EmailIngested"; iconDomain?: string };
+  | { type: "FeedCreated"; feedId: FeedId }
+  | { type: "EmailIngested"; feedId: FeedId; iconDomain?: string };