[Bug] MCP OAuth tokens for Google Workspace accounts require re-authorization every session

The OAuth token refresh issue reported in #21333 persists. Every new Claude Code session requires manual re-authorization for Google Workspace (institutional) accounts accessed via MCP servers.

Environment:

• Claude Code on macOS (Darwin 25.3.0, Apple Silicon)
• Google Workspace MCP server (mcp__google_workspace)
• Institutional Google Workspace account (.edu.pe domain)

Behavior:

• Personal Gmail (@gmail.com): tokens persist across sessions — no re-auth needed.
• Institutional Google Workspace (@pucp.edu.pe): requires full OAuth re-authorization at the start of every session.

Expected: Stored refresh tokens should be used to obtain new access tokens automatically, without requiring user interaction each session.

Impact: For users who rely on institutional Google Workspace accounts daily, this adds friction to every session start.

Ref: #21333