feat(frontend): login with center URL and consume center-issued guild tokens

src/lib/auth-storage.ts

@@ -1,4 +1,5 @@
 export type AuthSession = {
+  centerApiBase: string
   accessToken: string
   refreshToken: string
   tokenType: string
@@ -6,6 +7,17 @@ export type AuthSession = {
     id: string
     email: string
   }
+  guilds: Array<{
+    nodeId: string
+    name: string
+    endpoint: string
+    status: 'active' | 'offline' | 'revoked'
+  }>
+  guildAccessTokens: Array<{
+    guildNodeId: string
+    token: string
+    tokenType: string
+  }>
 }
 
 const KEY = 'fabric.auth.session.v1'