fix: address PR #19284 review comments

- Remove redundant Promise.race in McpToolInvocation.execute (event listener leak)
- Propagate AbortSignal to all press_key calls (submitKey + typeCharByChar)
- Call this.close() on connectMcp failure (zombie process leak)
- Set showInDialog: false for all browser settings
- Remove debug log truncation in analyzeScreenshot
- Fix misleading --experimental-vision error message
- Replace any casts with typed TestableConfirmation interface in tests
- Update license year to 2026 in all browser agent files
- Merge duplicate imports in mcpToolWrapper
- Add sync comment to BrowserAgentCustomConfig
- Update subagents.md Chrome requirement wording
- Regenerate settings docs

docs/core/subagents.md

@@ -96,7 +96,7 @@ Gemini CLI comes with the following built-in subagents:
 
 The browser agent requires:
 
-- **Chrome** version 144 or later installed on your system.
+- **Chrome** version 144 or later (any recent stable release will work).
 - **Node.js** with `npx` available (used to launch the
   [`chrome-devtools-mcp`](https://www.npmjs.com/package/chrome-devtools-mcp)
   server).
@@ -193,6 +193,9 @@ captures a screenshot and sends it to the vision model for analysis. The model
 returns coordinates and element descriptions that the browser agent uses with
 the `click_at` tool for precise, coordinate-based interactions.
 
+> **Note:** The visual agent requires API key or Vertex AI authentication. It is
+> not available when using Google Login.
+
 ## Creating custom subagents
 
 You can create your own subagents to automate specific workflows or enforce