DUNGEONS-34: implement Webka local streaming app

Co-authored-by: multica-agent <github@multica.ai>

backend/Cargo.toml

@@ -0,0 +1,27 @@
+[package]
+name = "webka"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+axum = { version = "0.8", features = ["ws"] }
+tokio = { version = "1", features = ["full"] }
+sqlx = { version = "0.8", features = ["runtime-tokio", "sqlite"] }
+argon2 = "0.5"
+rand = "0.8"
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"
+uuid = { version = "1", features = ["v4"] }
+sha2 = "0.10"
+hmac = "0.12"
+hex = "0.4"
+mdns-sd = "0.13"
+local-ip-address = "0.6"
+tower-http = { version = "0.6", features = ["fs", "set-header"] }
+futures-util = "0.3"
+
+[dev-dependencies]
+tokio-tungstenite = "0.29"
+tower = { version = "0.5", features = ["util"] }
+http-body-util = "0.1"
+tempfile = "3"