Support multiple macOS WeChat app profiles

[richardzone]

Summary

• add a global --profile option so config, keys, daemon state, and cache can be isolated per WeChat app/account
• add wx init --app, --bundle-id, --db-dir, and --wechat-process selectors
• make the macOS scanner choose the correct WeChat process by app bundle path or bundle id instead of assuming a single PID
• isolate per-profile daemon endpoints, including Windows named pipes

Why

On macOS, users can run multiple WeChat app bundles such as /Applications/WeChat.app and /Applications/WeChat2.app. Both main processes are named WeChat, so pgrep -x WeChat can return multiple PIDs and the CLI cannot safely know which instance to scan. The previous single config/cache/socket layout also made it hard to keep two accounts separate.

Validation

• cargo test --locked
• git diff --check
• manually verified two macOS app profiles against /Applications/WeChat.app and /Applications/WeChat2.app using wx --profile ... sessions