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>

tests/lembas-login.test.ts

@@ -88,7 +88,7 @@ function lembas(o: Partial<Pick<Fake, "approveAfter" | "deny" | "protocol" | "mo
       if (u.pathname === "/api/device/code") {
         const body = (await req.json()) as Record<string, string>
         expect(body.client_id).toStartWith("lembas-cli ")
-        expect(body.scope).toBe("models library link")
+        expect(body.scope).toBe("models memory link")
         return Response.json({ device_code: "dev-123", user_code: "CDFG-HJKM", verification_uri: `${base}/device`, verification_uri_complete: `${base}/device?code=CDFG-HJKM`, expires_in: 600, interval: 1 })
       }
       if (u.pathname === "/api/device/token") {