Migrate to new @welshman/domain + instance-based @welshman/app API

Adopts the rewritten welshman API: the removed @welshman/util helpers
(Profile/List/Room/Handler/Encryptable) are now Reader/Builder classes in
@welshman/domain, and @welshman/app dropped its global singletons for an App
instance + app.use(Plugin) registry.

- src/app/welshman.ts is now the app bootstrap + session-state module (one shared
  App instance, multi-account sessions/login, app-wide reactive views) rather than
  a compat shim re-exporting the old globals.
- Rewrote ~100 callers to use app.use(Plugin) directly (thunks, profiles, relays,
  rooms, zaps, tags, wot, feeds, sync); thunk helpers are now thunk methods.
- Added @welshman/domain dependency.
- Resolved residual gaps (storage hydration via plugin.onItem/wrapManager/Plaintext,
  relay-list mutators, search-relay list, outbox #d filter).

Best-effort: no toolchain/linking available, so this is not build- or
type-checked. Remaining judgment calls are flagged with TODO(welshman-migration).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BsMjvv7krpZeHK1Njeneru

src/app/components/ChatMessageEmojiButton.svelte

@@ -1,7 +1,8 @@
 <script lang="ts">
   import type {NativeEmoji} from "emoji-picker-element/shared"
   import type {TrustedEvent} from "@welshman/util"
-  import {sendWrapped} from "@welshman/app"
+  import {app} from "@app/welshman"
+  import {Wraps} from "@welshman/app"
   import SmileCircle from "@assets/icons/smile-circle.svg?dataurl"
   import Icon from "@lib/components/Icon.svelte"
   import EmojiButton from "@lib/components/EmojiButton.svelte"
@@ -15,7 +16,7 @@
   const {event, pubkeys}: Props = $props()
 
   const onEmoji = (emoji: NativeEmoji) =>
-    sendWrapped({
+    app.use(Wraps).publish({
       event: makeReaction({event, content: emoji.unicode, protect: false}),
       recipients: pubkeys,
       pow: 16,