fix: MetaMask 13.40 network picker selector updates

[Maksandre]

Summary

Nightly Playwright runs went red after MetaMask shipped 13.40, which replaced the Default/Custom tabbed network menu with a unified "Select network" modal.

Previously red tests (scheduled runs on main):

• Metamask: inside › Can connect to existing network — picker button now reads Network: <name>, so the exact-text assertion failed
• Metamask: inside › Can connect to existing testnet — the Custom tab no longer exists
• Metamask: inside › Can add a custom network and an existing network — same missing Custom tab

Root cause

MetaMask 13.40 merged Popular/Custom tabs into one list where every network row carries its display name as data-testid, and the picker button label gained a Network: prefix.

Fix

• switchNetwork: removed the tab click, selects networks by name testid in the unified modal, asserts with toContainText. The networkType parameter is deprecated and ignored (kept for backward compatibility).
• Tests: addCustomNetwork now targets the local anvil node (http://localhost:8545, chain 31337) instead of rpc-campnetwork.xyz. MetaMask 13.40 validates the RPC (fetches its chain ID) before enabling Save, and that external RPC was returning 503 — local anvil makes the tests hermetic.
• Docs: updated skills/w3wallets references for the deprecated parameter.
• Version: 1.0.0-beta.11 → 1.0.0-beta.12.

Test plan

• All 3 previously-red tests pass locally against MetaMask 13.40
• Full local suite green (remaining occasional local-only erc20 flakes are pre-existing cold-start timeouts, pass on rerun and in CI)
• CI green

🤖 Generated with Claude Code