v6.3.1: iOS subdomain cookie fix + regression tests

This release fixes iOS cookie domain handling issues affecting WebView and subdomains.

Fixed (iOS)

• Preserve leading-dot domains when setting cookies on iOS (.example.com).
• Validate domains without mutating the original cookie domain value.
• Use consistent domain matching for WebKit cookie reads (get(url, true)).
• import RCTBridgeModule only for old architecture builds to avoid architecture-specific integration issues.

Tests and CI

• Added Swift regression tests for domain normalization, validation, and subdomain matching.
• Added swift test execution in the macOS CI pipeline.

Example app

• Added manual domain input flow for cookie testing.
• Each new submission adds a new cookie and refreshes available cookies from shared/WebKit stores.

Fixes #2