Usage is money per currency, no credits; login asks for memory

The login asks the server for the memory scope in place of library (the
server accepts both; library is no longer offered for new tokens).

/v1/usage is read in the server's 2.0 shape: no plan, balance, credit
costs or windows. The status bar shows what the month has cost so far and
/usage the month's tokens and cost and this device's tokens, each
currency's amount on its own (month.cost_by_currency, else cost_money in
currency). The credit wording is gone.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/app.ts

@@ -294,7 +294,8 @@ export function createApp(o: AppOptions): App {
   let contextFrom = "the instance"
 
   // library: lembas — the account's library through the instance's /mcp, in place of this
-  // machine's. Needs the one instance logged in to, with a token that has the library scope.
+  // machine's. Needs the one instance logged in to, with a token that has the memory scope (or
+  // the older library).
   const lembasLibrary = memoryOnServer ? lembasLibraryServer(loaded.warnings) : undefined
   if (lembasLibrary) loaded.mcp[LIBRARY_SERVER] = lembasLibrary
   // Without a way to the server's memory, this machine's is used for now.