Fix misleading comment and incorrect Go terminology

- config.go: Clarify that package-level defaults are for efficiency, not temporary
- jsonrpc.go: Correct "thread" to "goroutine" (Go uses goroutines, not threads)

After thorough review of all reported issues:
- processInputPacket early nil check is correct double-checked locking (not a race)
- Async audio source switching is intentional design for 30-60s HDMI init time
- TypeScript JSON.parse is safe (backend controls data, React catches errors)

Only actual terminology issues needed fixing.

config.go

@@ -141,8 +141,8 @@ func (c *Config) SetDisplayRotation(rotation string) error {
 
 const configPath = "/userdata/kvm_config.json"
 
-// it's a temporary solution to avoid sharing the same pointer
-// we should migrate to a proper config solution in the future
+// Default configuration structs used to create independent copies in getDefaultConfig().
+// These are package-level variables to avoid repeated allocations.
 var (
 	defaultJigglerConfig = JigglerConfig{
 		InactivityLimitSeconds: 60,

jsonrpc.go

@@ -499,7 +499,7 @@ type RPCHandler struct {
 	Params []string
 }
 
-// call the handler but recover from a panic to ensure our RPC thread doesn't collapse on malformed calls
+// call the handler but recover from a panic to ensure our RPC goroutine doesn't collapse on malformed calls
 func callRPCHandler(logger zerolog.Logger, handler RPCHandler, params map[string]any) (result any, err error) {
 	// Use defer to recover from a panic
 	defer func() {