What does this PR do?

The WhatsApp gateway bridge runs npm install to set up its Node dependencies on first connect. That call previously used the default 60s subprocess timeout, which fired on slower NAS/container hosts and aborted the install partway through. The default was raised to 300s and an env override (WHATSAPP_NPM_INSTALL_TIMEOUT) was added; this PR adds regression coverage so neither change can silently regress.

Related Issue

Fixes #14980

Type of Change

• ✅ Tests (adding or improving test coverage)

Changes Made

• tests/gateway/test_whatsapp_connect.py:
  • Extract the node_modules-missing predicate into a shared TestConnectCleanup static helper to deduplicate setup across the new tests.
  • Add test_npm_install_uses_default_timeout — asserts subprocess.run is called with timeout=300 when WHATSAPP_NPM_INSTALL_TIMEOUT is unset.
  • Add test_npm_install_honors_env_override — asserts WHATSAPP_NPM_INSTALL_TIMEOUT=600 overrides the default and is passed through to subprocess.run.

How to Test

1. python -m pytest tests/gateway/test_whatsapp_connect.py -q -o 'addopts='
2. Both new tests pass; existing tests in the file are unaffected.
3. git diff --check is clean.

Checklist

Code

• I've read the Contributing Guide
• My commit messages follow Conventional Commits (test(whatsapp):)
• I searched for existing PRs to make sure this isn't a duplicate
• My PR contains only changes related to this fix/feature (no unrelated commits)
• I've run the targeted test file and it passes
• I've added tests for my changes (this PR is the tests)
• I've tested on my platform: macOS 15.6.1

Documentation & Housekeeping

• I've updated relevant documentation — N/A (test-only)
• I've updated cli-config.yaml.example if I added/changed config keys — N/A
• I've updated CONTRIBUTING.md or AGENTS.md if I changed architecture or workflows — N/A
• I've considered cross-platform impact (Windows, macOS) — tests stub subprocess.run, no platform-specific behavior
• I've updated tool descriptions/schemas if I changed tool behavior — N/A

Screenshots / Logs

$ python -m pytest tests/gateway/test_whatsapp_connect.py -q -o 'addopts='
... all tests pass ...