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/channelGrant.ts

@@ -8,16 +8,30 @@ interface ChannelGrant {
   mode: 'enc' | 'raw';
   role: 'owner' | 'member';
   keys: ParsedChannelLink['keys'];
+  /** 仅供被邀请方在收件箱显示,在加密 payload 内,服务端不可见 */
+  name?: string;
+  invitedBy?: string;
 }
 
-export async function sealChannelGrant(link: string, recipient: string, publicKey: JsonWebKey): Promise<string> {
+export interface InvitationMeta { name?: string; invitedBy?: string }
+
+export async function sealChannelGrant(link: string, recipient: string, publicKey: JsonWebKey, meta: InvitationMeta = {}): Promise<string> {
   const parsed = parseChannelLink(link);
   if (!parsed.ok) throw new Error('空间凭据格式无效');
   const grant: ChannelGrant = { v: 1, channelId: parsed.link.id, mode: parsed.link.mode,
-    role: parsed.link.isOwner ? 'owner' : 'member', keys: parsed.link.keys };
+    role: parsed.link.isOwner ? 'owner' : 'member', keys: parsed.link.keys,
+    ...(meta.name ? { name: meta.name } : {}), ...(meta.invitedBy ? { invitedBy: meta.invitedBy } : {}) };
   return encryptInvitation(JSON.stringify(grant), recipient, grant.channelId, publicKey);
 }
 
+/** 只读取显示用的元信息;解不开或没有这些字段时返回空,调用方回退到空间 ID */
+export async function peekChannelGrant(payload: string, recipient: string, channelId: string, privateKey: JsonWebKey): Promise<InvitationMeta> {
+  try {
+    const grant = JSON.parse(await decryptInvitation(payload, recipient, channelId, privateKey)) as Partial<ChannelGrant>;
+    return { ...(typeof grant.name === 'string' ? { name: grant.name } : {}), ...(typeof grant.invitedBy === 'string' ? { invitedBy: grant.invitedBy } : {}) };
+  } catch { return {}; }
+}
+
 export async function openChannelGrant(payload: string, recipient: string, channelId: string, privateKey: JsonWebKey,
   role: 'owner' | 'member', origin: string): Promise<ParsedChannelLink> {
   const plain = await decryptInvitation(payload, recipient, channelId, privateKey);