Add font size setting for Claude Code panel, independent of VS Code zoom

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

The Claude Code VS Code extension only supports scaling text via VS Code's global window zoom (Ctrl +/Ctrl -), which resizes the entire editor UI together with the Claude Code chat panel. Users who want larger, more readable text in the chat panel (e.g. for accessibility or personal preference) are forced to zoom the whole VS Code window, which shrinks/enlarges code editors, tabs, and other panels they don't want to change.

Proposed Solution

Add a dedicated font-size setting for the Claude Code panel, independent of VS Code's global zoom — e.g. a claude-code.chat.fontSize (or similar) setting in settings.json, and/or a small font-size control (A-/A+ buttons or a slider) inside the panel's own UI (near the settings gear icon). This should scale only the text rendered inside the Claude Code webview, leaving the rest of the VS Code interface untouched.

Alternative Solutions

Currently the only workaround is VS Code's global Window: Zoom Level setting or Ctrl +/Ctrl -, which affects the entire window, not just the Claude Code panel. Other AI/chat extensions in VS Code (and standalone apps) commonly expose a scoped font-size or zoom control for their own webview panel — that would be a reasonable precedent to follow.

Priority

Low - Nice to have

Feature Category

Configuration and settings

Use Case Example

User opens the Claude Code panel in VS Code.
Chat text is too small to read comfortably, but the user doesn't want to zoom their code editor.
User opens Settings, searches "Claude Code font size", sets it larger (or uses an in-panel A+ control).
Only the chat panel text becomes larger; the rest of the VS Code UI is unaffected.

Additional Context

Similar to how browsers/apps like Slack or Discord let you scale in-app text independently of OS/browser zoom.