Model toOthers() with simulated socket IDs

[luisdalmolin]

Problem

v0.5 preserves Laravel's socket exclusion metadata, but the simulator does not yet use it. A broadcast sent with toOthers() is therefore delivered back to the originating simulated page.

Proposed direction

Give each simulated Echo/Pusher session a stable socket ID and exclude a replay when the captured socket matches the target session.

Acceptance criteria

• Each installed session exposes or internally owns a stable simulated socket ID.
• A captured socket ID matching the target session produces an explicit excluded outcome rather than delivery.
• Other sessions still receive the same captured broadcast.
• broadcastToEveryone() remains deliverable to all subscribed sessions.
• Multi-page browser coverage verifies originator exclusion and peer delivery.