feat: multi-port UDP listener with data dump

Listen on three AC telemetry ports simultaneously (9996, 10101, 5005).
Dump received data to per-feed files under ./data/<session>/.
Notify on console for each received packet.

- Port 9996: AC built-in (ksudp), binary with 4-byte length framing
- Port 10101: Telemetry Tool plugin, binary with 4-byte length framing
- Port 5005: AC Lua plugin, JSON with newline-separated records
- Configurable bind address via RUSTY_TELEMETRY_BIND (default 127.0.0.1)
- Buffered file I/O via tokio BufWriter
- Graceful shutdown with flush on Ctrl+C
- Startup banner showing feed status
- Bumped version to 0.2.0, added futures dependency

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rusty-telemetry"
-version = "0.1.0"
+version = "0.2.0"
 edition = "2021"
 description = "Sim racing telemetry receiver and analyzer"
 
@@ -9,3 +9,4 @@ tokio = { version = "1", features = ["full"] }
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 chrono = "0.4"
+futures = "0.3"