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/routes/admin/emails.tsx

@@ -158,7 +158,7 @@ emailsRouter.get("/feeds/:feedId/emails", async (c) => {
   const message = c.req.query("message");
   const count = Number(c.req.query("count") || "0");
 
-  const id = FeedId.fromTrusted(feedId);
+  const id = FeedId.unchecked(feedId);
   const feedConfig = await repo.getConfig(id);
   const feedMetadata = await repo.getMetadata(id);
 
@@ -656,7 +656,7 @@ emailsRouter.post("/emails/:emailKey/delete", async (c) => {
       return c.text("Feed ID is required", 400);
     }
 
-    const feed = await repo.load(FeedId.fromTrusted(feedId));
+    const feed = await repo.load(FeedId.unchecked(feedId));
 
     await repo.deleteEmail(emailKey);
     if (feed) {
@@ -691,7 +691,7 @@ emailsRouter.post("/feeds/:feedId/emails/bulk-delete", async (c) => {
     (c.req.header("Accept") || "").includes("application/json");
 
   try {
-    const feed = await repo.load(FeedId.fromTrusted(feedId));
+    const feed = await repo.load(FeedId.unchecked(feedId));
 
     if (!feed) {
       return wantsJson