fix: context limit display uses stale model after model switch #35072

Description

After switching models mid-session, the context limit percentage in the sidebar continues to display based on the previous model's context window, not the currently selected model.

Example

1. Start session with model A (128k context)
2. Use model A for several messages, context shows 50% used (64k/128k)
3. Switch to model B (32k context)
4. Context still shows 50% used, but should show 200% (64k/32k) or at least use model B's limit

Root Cause

In the sidebar context component, the context limit is calculated using the model from the last assistant message, not the currently selected model:

\\ ypescript
const model = props.api.state.provider.find((item) => item.id === last.providerID)?.models[last.modelID]
\\

Proposed Fix

Use the currently selected model for context limit display when available:

\\ ypescript
const currentModel = local.model.current()
const model = currentModel
? props.api.state.provider.find((item) => item.id === currentModel.providerID)?.models[currentModel.modelID]
: props.api.state.provider.find((item) => item.id === last.providerID)?.models[last.modelID]
\\

MiMo Code Reference

This fix has been implemented in MiMo Code PR #1522: XiaomiMiMo/MiMo-Code#1522

Environment

• OpenCode version: 1.17.8
• OS: Windows 11
• Terminal: PowerShell