feat(web): discord-style chat, members pane, invitations and optimistic send [CI]

- chat: left-aligned discord-style messages with grouped senders, hover
  actions, an auto-growing composer and file cards
- send: render messages and files locally first and replace the
  placeholder when the worker publishes the real item; failures keep the
  text with a retry action
- navigation: space rail plus a flatter channel list with the space name
  header and collapsible groups
- members: right pane tabs (files / members) grouped by online, offline
  and pending users, with a prominent invite action and a top bar shortcut
- notifications: toast host for invite results; invitees get a toast with
  an accept action, and the invitation payload now carries the space name
  and inviter inside the encrypted grant
- users over devices: drop device names, the device list and device
  rename/release; senders show the account (guests show as guest) and the
  share panel only keeps links
- follow contract 7.0.0 (max_members, members_used, members_full, /join)
- docs: ui-design and frontend updated for the new layout and concepts

web/src/core-bridge/worker/shareDraft.ts

@@ -16,7 +16,7 @@ function newTextEntry(text: string): { item: TextItem; entry: Extract<ManifestEn
   const ts = Date.now();
   const localId = `draft-text-${crypto.randomUUID()}`;
   return {
-    item: { id: localId, kind: 'text', ts, deviceId: '创建者', state: { kind: 'complete' }, text },
+    item: { id: localId, kind: 'text', ts, state: { kind: 'complete' }, text },
     entry: { t: 'text', localId, text, ts },
   };
 }