Step 4: Introduction and rendezvous circuits

[igor53627]

Parent Issue

Part of #23 (Onion service support)

Overview

Build specialized circuits for HS introduction and rendezvous points.

Tasks

• Add circuit builder for specific relay targets
• Build introduction circuit to chosen intro point
• Build rendezvous circuit to random relay
• Send ESTABLISH_RENDEZVOUS cell with random cookie
• Handle circuit failures and retry logic

Technical Notes

• Intro circuit: Guard -> Middle -> IntroPoint
• Rend circuit: Guard -> Middle -> RendPoint
• Both need to be built before INTRODUCE1 can be sent

Dependencies

• Step 3: HS descriptor parsing #39 (HS descriptor parsing - need intro points)

Acceptance Criteria

• Can build circuit to specific relay
• ESTABLISH_RENDEZVOUS succeeds
• Circuits are properly isolated from regular circuits