Rewrite domain objects as a Reader/Builder split

Replace the single DomainObject/EncryptableList classes with a read/write split
that removes the optional-event ambiguity:

- base.ts: EventReader<P> (static kind; fromEvent(event, signer?) eagerly computes
  a generic `plain`, validates leniently, throws-or-passes; lazy method accessors;
  group/protect/expires + extraTags carry-over; builder()) and EventBuilder<P>
  (chainable setters, buildTags/buildContent, validate-on-emit).
- List.ts: ListReader/ListBuilder for NIP-51 lists (decrypt-on-read into `plain`,
  re-encrypt-on-emit, tag mutators).
- Every kind converted to a <Noun> reader + <Noun>Builder pair; membership ops
  split into per-kind reader/builder pairs over a shared abstract base.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01V67tPYdvh1qCkjEBhJGZUR

packages/domain/src/MessagingRelayList.ts

@@ -1,25 +1,33 @@
 import {uniqBy} from "@welshman/lib"
 import {MESSAGING_RELAYS, getTagValues, normalizeRelayUrl} from "@welshman/util"
-import {EncryptableList} from "./List.js"
+import {ListReader, ListBuilder} from "./List.js"
 
 // NIP-17 kind-10050 messaging/inbox relays. Entries are marker-less
 // ['relay', url] tags (NOT NIP-65 'r' tags with read/write markers, and the
 // RelayMode.Messaging marker is not used per-tag here). `urls()` drives where
 // encrypted DM gift-wraps are sent and fetched, so it stays a flat, normalized
 // set. Identical structure to BlockedRelayList/SearchRelayList.
-export class MessagingRelayList extends EncryptableList {
-  readonly kind = MESSAGING_RELAYS
+export class MessagingRelayList extends ListReader {
+  static kind = MESSAGING_RELAYS
 
   urls() {
     return uniqBy(normalizeRelayUrl, getTagValues("relay", this.tags()))
   }
 
+  builder() {
+    return this.seedList(new MessagingRelayListBuilder())
+  }
+}
+
+export class MessagingRelayListBuilder extends ListBuilder {
+  static kind = MESSAGING_RELAYS
+
   addRelay(url: string) {
     return this.addPublicTags(["relay", normalizeRelayUrl(url)])
   }
 
   removeRelay(url: string) {
-    return this.removeTagsWithValue(url)
+    return this.removeTagsWithValue(normalizeRelayUrl(url))
   }
 
   setRelays(urls: string[]) {