feat: remote value

[idoros]

This PR adds RemoteValue for cross environment state sharing with auto synchronization on disconnect -> reconnect.

The motivation for this API is that the current event emitter subscribe/unsubscribe pattern does not maintain state/version and therefore cannot automatically re-synchronize after a reconnection. While it is not intended as a replacement for all event-emitter use cases (e.g., streaming logs or other events that have no remote state), it provides a simple and transparent way to handle most stateful cross-environment connections. RemoteValue preserves state and re-establishes synchronization automatically.

Key Features

• Subscribe/unsubscribe pattern for value changes
• Version tracking to detect stale values
• Auto-reconnect and sync on environment reconnection
• stream() method for immediate value + subscription
• getValue() for one-time value retrieval

Technical Details

• Communication layer treats RemoteValue methods specially via dot-notation (counter.subscribe, counter.reconnect, etc.)
• Version tracking on both sides: subscribers track their current version, reconnection syncs if mismatch detected
• On environment reconnection, all RemoteValue subscriptions automatically call reconnect() with their current version
• Only notifies subscribers when value actually changes (identity comparison)
• Reconnect returns {value, version} if out-of-sync, or null if versions match