[BUG] VSCode extension model picker does not show active [1m] extended context indicator

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

When using a model with the [1m] extended context suffix (e.g., claude-opus-4-6[1m]), set via ~/.claude/settings.json or the /model opus[1m] command, the VSCode extension does not reflect the [1m] setting in two places:

1. Model picker: Shows claude-opus-4-6 as "Custom model" with no indication that [1m] is active
2. /context command: Shows 105.2k / 200k (53%) instead of the 1M token limit. The terminal CLI correctly shows the 1M limit for the same configuration.

What Should Happen?

1. The model picker should clearly indicate that [1m] extended context is active (e.g., claude-opus-4-6 · 1M context)
2. The /context command should display the correct 1M token limit, matching the terminal CLI behavior

Error Messages/Logs

Steps to Reproduce

1. Set "model": "claude-opus-4-6[1m]" in ~/.claude/settings.json
2. Open VSCode with the Claude Code extension
3. Click the model picker → shows claude-opus-4-6 as "Custom model" with no [1m] indicator
4. Run /context in the extension → shows 105.2k / 200k (53%)
5. Run /context in the terminal CLI → correctly shows the 1M token limit

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.47 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

VS Code integrated terminal

Additional Information

The /model command and settings.json both work correctly to configure the model — the actual model behavior appears to function as expected. This is a display-only bug where the extension UI fails to parse/reflect the [1m] suffix in both the model picker and context usage display.