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/accountChannels.ts

@@ -25,7 +25,7 @@ export async function recoverAccountChannels(username: string, keys: InvitationK
         creatorAccount: info.creator_account ?? undefined, name: info.settings.name ?? undefined,
         link: session.link(self.location.origin), ...(grant.role === 'owner' ? { ownerLink: session.link(self.location.origin, 'owner') } : {}),
         endpointSecret: new Uint8Array(32), createdAt: info.created_at, modifiedAt: grant.created_at, expiresAt: info.expires_at,
-        seats: info.settings.seats, maxDownloads: info.settings.file_max_downloads };
+        maxMembers: info.settings.max_members, maxDownloads: info.settings.file_max_downloads };
       if (signal.aborted) throw new DOMException('账号已切换', 'AbortError');
       await importResources([resource]);
     } finally { session.dispose(); }