claude.ai Gmail MCP: plain-text drafts get URLs rewritten to google.com/url redirect wrappers

## Description

When creating a Gmail draft through the claude.ai Gmail MCP connector (`create_draft` / `update_draft`) with only the plain-text `body` field, any bare URLs in the body are rewritten by Gmail's composer into Google redirect links of the form:

`https://www.google.com/url?q=https://example.com&source=gmail&ust=&sa=E`

These wrapped links are what actually goes out when the draft is sent. To recipients (and spam filters) they look like tracking links — a real problem for professional correspondence.

## Repro

1. Call `mcp__claude_ai_Gmail__create_draft` with a plain-text `body` containing a bare URL (e.g. `https://arxiv.org/abs/XXXX.XXXXX`), no `htmlBody`.
2. Open the draft in the Gmail web UI: the URL renders as a link whose href is the google.com/url wrapper.
3. Sending the draft delivers the wrapped href.

## Workaround

Pass `htmlBody` with explicit `` anchors — Gmail leaves a proper HTML part alone. (Observed: 13/13 drafts created body-only were wrapped; all fixed by updating with htmlBody.)

Environment: Claude Code CLI on macOS, claude.ai Gmail connector, 2026-09-01.

Start at the create_draft and update_draft entry points for the claude.ai Gmail MCP connector and reproduce the body-only draft behavior with a bare URL. Compare that result with an update using htmlBody and explicit anchors. Done means determining the relevant implementation scope and choosing a documented or automated behavior that prevents unintended google.com/url wrappers.

Scritto dal modello di indicizzazione a partire dal testo della issue.