feat: add Rust reverse proxy with JSON logging

- Axum-based API server with Unix socket and TCP support
- Custom tracing formatters for Railway-compatible JSON logs
- SvelteKit hooks and Vite plugin for unified logging
- Justfile updated for concurrent dev workflow with hl log viewer

Justfile

@@ -1,13 +1,23 @@
+default:
+	just --list
+
 dev:
-    bun run --cwd web dev
+    just dev-json | hl --config .hl.config.toml -P
+
+dev-json:
+    LOG_JSON=true UPSTREAM_URL=/tmp/xevion-api.sock bunx concurrently --raw --prefix none "bun run --silent --cwd web dev --port 5173" "cargo watch --quiet --exec 'run --quiet -- --listen localhost:8080 --listen /tmp/xevion-api.sock --downstream http://localhost:5173'"
 
 setup:
     bun install --cwd web
+    cargo build
 
 build:
     bun run --cwd web build
+    cargo build --release
 
 check:
     bun run --cwd web format
     bun run --cwd web lint
     bun run --cwd web check
+    cargo clippy --all-targets
+    cargo fmt --check