feat: Controller support, performance enchancements, multi-stage images, fixes (#304)

## Description
Oops.. another massive PR 🥲 

This PR contains multiple improvements and changes.

Firstly, thanks gst-wayland-display's PR
[here](https://github.com/games-on-whales/gst-wayland-display/pull/20).
NVIDIA path is now way more efficient than before.

Secondly, adding controller support was a massive hurdle, requiring me
to start another project
[vimputti](https://github.com/DatCaptainHorse/vimputti) - which allows
simple virtual controller inputs in isolated containers. Well, it's not
simple, it includes LD_PRELOAD shims and other craziness, but the
library API is simple to use..

Thirdly, split runner image into 3 separate stages, base + build +
runtime, should help keep things in check in future, also added GitHub
Actions CI builds for v2 to v4 builds (hopefully they pass..).

Fourth, replaced the runner's runtime Steam patching with better and
simpler bubblewrap patch, massive thanks to `games-on-whales` to
figuring it out better!

Fifth, relay for once needed some changes, the new changes are still
mostly WIP, but I'll deal with them next time I have energy.. I'm spent
now. Needed to include these changes as relay needed a minor change to
allow rumble events to flow back to client peer.

Sixth.. tons of package updates, minor code improvements and the usual. 

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* End-to-end gamepad/controller support (attach/detach, buttons, sticks,
triggers, rumble) with client/server integration and virtual controller
plumbing.
  * Optional Prometheus metrics endpoint and WebTransport support.
  * Background vimputti manager process added for controller handling.

* **Improvements**
  * Multi-variant container image builds and streamlined runtime images.
  * Zero-copy video pipeline and encoder improvements for lower latency.
  * Updated Steam compat mapping and dependency/toolchain refreshes.

* **Bug Fixes**
* More robust GPU detection, input/fullscreen lifecycle,
startup/entrypoint, and container runtime fixes.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: DatCaptainHorse <DatCaptainHorse@users.noreply.github.com>

packages/server/src/p2p/p2p.rs

@@ -1,3 +1,4 @@
+use anyhow::Result;
 use libp2p::futures::StreamExt;
 use libp2p::multiaddr::Protocol;
 use libp2p::{
@@ -11,7 +12,6 @@ use libp2p_ping as ping;
 use libp2p_stream as stream;
 use libp2p_tcp as tcp;
 use libp2p_yamux as yamux;
-use std::error::Error;
 use std::sync::Arc;
 use tokio::sync::Mutex;
 
@@ -46,7 +46,7 @@ pub struct NestriP2P {
     swarm: Arc<Mutex<Swarm<NestriBehaviour>>>,
 }
 impl NestriP2P {
-    pub async fn new() -> Result<Self, Box<dyn Error>> {
+    pub async fn new() -> Result<Self> {
         let swarm = Arc::new(Mutex::new(
             libp2p::SwarmBuilder::with_new_identity()
                 .with_tokio()
@@ -69,14 +69,16 @@ impl NestriP2P {
         Ok(NestriP2P { swarm })
     }
 
-    pub async fn connect(&self, conn_url: &str) -> Result<NestriConnection, Box<dyn Error>> {
+    pub async fn connect(&self, conn_url: &str) -> Result<NestriConnection> {
         let conn_addr: Multiaddr = conn_url.parse()?;
 
         let mut swarm_lock = self.swarm.lock().await;
         swarm_lock.dial(conn_addr.clone())?;
 
         let Some(Protocol::P2p(peer_id)) = conn_addr.clone().iter().last() else {
-            return Err("Invalid connection URL: missing peer ID".into());
+            return Err(anyhow::Error::msg(
+                "Invalid multiaddr: missing /p2p/<peer_id>",
+            ));
         };
 
         Ok(NestriConnection {
@@ -88,10 +90,7 @@ impl NestriP2P {
 
 async fn swarm_loop(swarm: Arc<Mutex<Swarm<NestriBehaviour>>>) {
     loop {
-        let event = {
-            let mut swarm_lock = swarm.lock().await;
-            swarm_lock.select_next_some().await
-        };
+        let event = swarm.lock().await.select_next_some().await;
         match event {
             /* Ping Events */
             SwarmEvent::Behaviour(NestriBehaviourEvent::Ping(ping::Event {