Copilot session rate limit error gives no reset time or duration

- Copilot Chat Extension Version: v0.56.0
- VS Code Version: 1.128.0
- OS Version: Debian13 - amd64
- Feature (e.g. agent/edit/ask mode):
- Selected model (e.g. GPT 4.1, Claude 3.7 Sonnet): all
- Plan: Copilot Pro

**Description:**
I'm on GitHub Copilot Pro and repeatedly hit the session rate limit message: "You've hit your session rate limit. Please upgrade your plan or wait a moment for your limit to reset."

The message does not specify how long I need to wait. I tried again every few minutes over an extended period and kept getting the same error, with no indication of an actual reset time.

**Expected behavior:**
The error message should show a concrete reset time or countdown (e.g. "resets in 42 minutes" or "resets at 3:30 PM"), similar to how the monthly premium request usage shows a reset date.

**Steps to reproduce:**
1. Use Copilot Chat/Agent mode with a premium model (e.g. GPT-5.4) in VS Code.
2. Send several requests in succession.
3. Hit the session rate limit.
4. Retry after several minutes — same vague message persists.

**Screenshot attached.**