Add Rust server

Owns the database, PIN rotation and all LiveKit token minting. Kiosk
registration, session-stable joins, admin auth, layouts, branding, media
uploads and the hosted installer script.

server/Cargo.toml

@@ -0,0 +1,23 @@
+[package]
+name = "pistation-server"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+axum = { version = "0.8", features = ["macros"] }
+tokio = { version = "1", features = ["full"] }
+tower-http = { version = "0.6", features = ["cors", "fs", "trace"] }
+sqlx = { version = "0.8", features = ["runtime-tokio-rustls", "sqlite", "migrate"] }
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"
+jsonwebtoken = "9"
+argon2 = { version = "0.5", features = ["std"] }
+rand = "0.8"
+uuid = { version = "1", features = ["v4", "serde"] }
+chrono = { version = "0.4", features = ["serde"] }
+thiserror = "2"
+tracing = "0.1"
+tracing-subscriber = { version = "0.3", features = ["env-filter"] }
+dotenvy = "0.15"
+sha2 = "0.10"
+hex = "0.4"