chore: remove dead core/parmanode crate

The parmanode compatibility layer was scaffolded but never wired up —
zero imports or calls from anywhere in the codebase. Closes gitea#1.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

core/archipelago/Cargo.toml

@@ -34,7 +34,7 @@ futures-util = "0.3"
 archipelago-container = { path = "../container" }
 archipelago-security = { path = "../security" }
 archipelago-performance = { path = "../performance" }
-archipelago-parmanode = { path = "../parmanode" }
+
 
 # Database (optional for now - can use SQLite or skip)
 # sqlx = { version = "0.7", features = ["sqlite", "runtime-tokio-rustls"] }