feat: Fully use protobuf, fix controller issues and cleanup (#305)

## Description
### First commit
Restructured protobuf schemas to make them easier to use across
languages, switched to using them in-place of JSON for signaling as
well, so there's no 2 different message formats flying about. Few new
message types to deal with clients and nestri-servers better (not final
format, may see changes still).

General cleanup of dead/unused code along some bug squashing and package
updates.

TODO for future commits:
- [x] Fix additional controllers not doing inputs (possibly needs
vimputti changes)
- [x] ~~Restructure relay protocols code a bit, to reduce bloatiness of
the currently single file for them, more code re-use.~~
- Gonna keep this PR somewhat manageable without poking more at relay..
- [x] ~~Try to fix issue where with multiple clients, static stream
content causes video to freeze until there's some movement.~~
- Was caused by server tuned profile being `throughput-performance`,
causing CPU latency to be too high.
- [x] Ponder the orb


### Second + third commit
Redid the controller polling handling and fixed multi-controller
handling in vimputti and nestri code sides. Remove some dead relay code
as well to clean up the protocol source file, we'll revisit the meshing
functionality later.

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

* **New Features**
* Added software rendering option and MangoHud runtime config;
controller sessions now support reconnection and batched state updates
with persistent session IDs.

* **Bug Fixes**
* Restored previously-filtered NES-like gamepads so they connect
correctly.

* **Chores**
* Modernized dependencies and protobuf tooling, migrated to
protobuf-based messaging and streaming, and removed obsolete CUDA build
steps.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

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

packages/relay/internal/connections/datachannel.go

@@ -31,16 +31,18 @@ func NewNestriDataChannel(dc *webrtc.DataChannel) *NestriDataChannel {
 		}
 
 		// Decode message
-		var base gen.ProtoMessageInput
+		var base gen.ProtoMessage
 		if err := proto.Unmarshal(msg.Data, &base); err != nil {
 			slog.Error("failed to decode binary DataChannel message", "err", err)
 			return
 		}
 
-		// Handle message type callback
-		if callback, ok := ndc.callbacks["input"]; ok {
-			go callback(msg.Data)
-		} // We don't care about unhandled messages
+		// Route based on PayloadType
+		if base.MessageBase != nil && len(base.MessageBase.PayloadType) > 0 {
+			if callback, ok := ndc.callbacks[base.MessageBase.PayloadType]; ok {
+				go callback(msg.Data)
+			}
+		}
 	})
 
 	return ndc

packages/relay/internal/connections/messages.go

@@ -1,94 +0,0 @@
-package connections
-
-import (
-	"encoding/json"
-	"relay/internal/common"
-
-	"github.com/pion/webrtc/v4"
-)
-
-// MessageBase is the base type for any JSON message
-type MessageBase struct {
-	Type    string                 `json:"payload_type"`
-	Latency *common.LatencyTracker `json:"latency,omitempty"`
-}
-
-type MessageRaw struct {
-	MessageBase
-	Data json.RawMessage `json:"data"`
-}
-
-func NewMessageRaw(t string, data json.RawMessage) *MessageRaw {
-	return &MessageRaw{
-		MessageBase: MessageBase{
-			Type: t,
-		},
-		Data: data,
-	}
-}
-
-type MessageLog struct {
-	MessageBase
-	Level   string `json:"level"`
-	Message string `json:"message"`
-	Time    string `json:"time"`
-}
-
-func NewMessageLog(t string, level, message, time string) *MessageLog {
-	return &MessageLog{
-		MessageBase: MessageBase{
-			Type: t,
-		},
-		Level:   level,
-		Message: message,
-		Time:    time,
-	}
-}
-
-type MessageMetrics struct {
-	MessageBase
-	UsageCPU        float64 `json:"usage_cpu"`
-	UsageMemory     float64 `json:"usage_memory"`
-	Uptime          uint64  `json:"uptime"`
-	PipelineLatency float64 `json:"pipeline_latency"`
-}
-
-func NewMessageMetrics(t string, usageCPU, usageMemory float64, uptime uint64, pipelineLatency float64) *MessageMetrics {
-	return &MessageMetrics{
-		MessageBase: MessageBase{
-			Type: t,
-		},
-		UsageCPU:        usageCPU,
-		UsageMemory:     usageMemory,
-		Uptime:          uptime,
-		PipelineLatency: pipelineLatency,
-	}
-}
-
-type MessageICE struct {
-	MessageBase
-	Candidate webrtc.ICECandidateInit `json:"candidate"`
-}
-
-func NewMessageICE(t string, candidate webrtc.ICECandidateInit) *MessageICE {
-	return &MessageICE{
-		MessageBase: MessageBase{
-			Type: t,
-		},
-		Candidate: candidate,
-	}
-}
-
-type MessageSDP struct {
-	MessageBase
-	SDP webrtc.SessionDescription `json:"sdp"`
-}
-
-func NewMessageSDP(t string, sdp webrtc.SessionDescription) *MessageSDP {
-	return &MessageSDP{
-		MessageBase: MessageBase{
-			Type: t,
-		},
-		SDP: sdp,
-	}
-}