/usage and /status incorrectly prompt to /login before the first message

Description

Right after starting kimi, before sending the first message, running /usage shows:

Session usage
  No active session. Send /login to login.

/status shows the same text as a Warning row.

This is misleading: the user is signed in (the Plan usage section of the same panel loads account quotas fine). The actual reason is that on the v2 engine the session is created lazily on the first message — the startup screen itself says No session yet — one will be created on your first message. — so there is simply no session yet.

Steps to reproduce

1. Log in, then start kimi.
2. Before sending any message, run /usage (or /status).

Expected

The session-scoped sections degrade gracefully, e.g. /usage shows No token usage recorded yet. and /status shows no login warning, since being session-less at this point is normal.

Actual

Both commands surface requireSession()'s No active session. Send /login to login. error, which only makes sense on the v1 engine where a missing session means the user is not signed in.

Start by tracing the /usage and /status commands to requireSession() and compare their v2-engine behavior with the startup message stating that a session is created on the first message. Verify the session-scoped output before the first message and confirm that the Plan usage section still loads account quotas. Done means no misleading login warning and graceful no-usage output when no session exists.