refactor: tighten DDD boundaries on the Feed aggregate

Address five modeling tensions in one pass:

- Encapsulation: the Feed aggregate no longer exposes raw config/metadata
  (a shallow Readonly still leaked mutable arrays). It now offers
  intention-revealing accessors that return copies, plus
  toConfigSnapshot/toMetadataSnapshot for the repository and summary() for
  the global registry.
- feeds:list consistency: FeedRepository.save/saveConfig upsert the registry
  entry from feed.summary(), so services no longer mirror title/description/
  expiry by hand (the old add/updateInList footgun is gone).
- domain/feed.ts: drop the dead applySenderPolicy, internalise resolveExpiresAt
  and trimToByteBudget into the aggregate; feed.ts keeps only the shared
  isExpired predicate used by the read-model routes.
- Single edit path: remove editDetails; edit(patch, deps) is the sole config
  mutation, with a systematic expired guard. Renaming an expired feed now 403s.
- FeedId flows through the application and infrastructure signatures;
  fromTrusted/parse happen once at the edge, .value only at the serialisation
  boundaries (urls, feed-generator, feed-keys, logs, JSON).

347 tests green, tsc clean, Worker bundle builds.

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

src/routes/admin.tsx

@@ -9,6 +9,7 @@ import { logger } from "../infrastructure/logger";
 import { timingSafeEqual, checkProxyAuth } from "../infrastructure/auth";
 import { Layout, clampText } from "./admin/ui";
 import { FeedRepository } from "../infrastructure/feed-repository";
+import { FeedId } from "../domain/value-objects/feed-id";
 import { editFeedDetails } from "../application/feed-service";
 import {
   feedRssUrl,
@@ -996,12 +997,21 @@ app.post(
     try {
       const { title, description } = c.req.valid("json");
 
-      // In-place edit: only title/description, expiry untouched.
-      const result = await editFeedDetails(env, feedId, { title, description });
+      // Quick-edit: only title/description, expiry untouched.
+      const result = await editFeedDetails(env, FeedId.fromTrusted(feedId), {
+        title,
+        description,
+      });
 
       if (result.status === "not_found") {
         return c.json({ error: "Feed not found" }, 404);
       }
+      if (result.status === "expired") {
+        return c.json(
+          { error: "Feed has expired and cannot be modified." },
+          403,
+        );
+      }
 
       return c.json({ success: true });
     } catch (error) {