Remove concurrency config

Inference engines handle this now.

internal/config/config.go

@@ -20,9 +20,6 @@ type Config struct {
 	// Address is the host:port to listen on.
 	Address string `yaml:"address"`
 
-	// Concurrency is the number of concurrent requests to allow.
-	// Defaults to 1.
-	Concurrency int `yaml:"concurrency"`
 	// ShutdownTimeout is the maximum time to wait for graceful shutdown.
 	// Defaults to "30s".
 	ShutdownTimeout string `yaml:"shutdown_timeout"`
@@ -42,9 +39,6 @@ type Config struct {
 // ApplyDefaults sets default values for optional configuration fields.
 // Called automatically by Load before validation.
 func (cfg *Config) ApplyDefaults() {
-	if cfg.Concurrency == 0 {
-		cfg.Concurrency = 1
-	}
 	if cfg.ShutdownTimeout == "" {
 		cfg.ShutdownTimeout = "30s"
 	}

internal/config/config_test.go

@@ -11,7 +11,6 @@ import (
 func validConfig() string {
 	return `
 address: ":9090"
-concurrency: 2
 shutdown_timeout: "60s"
 
 llm:
@@ -55,12 +54,6 @@ func TestLoad(t *testing.T) {
 						cfg.Address, ":9090",
 					)
 				}
-				if cfg.Concurrency != 2 {
-					t.Errorf(
-						"Concurrency = %d, want 2",
-						cfg.Concurrency,
-					)
-				}
 				if cfg.ShutdownTimeout != "60s" {
 					t.Errorf(
 						"ShutdownTimeout = %q, want %q",
@@ -96,12 +89,6 @@ tts:
 						cfg.Address, ":8080",
 					)
 				}
-				if cfg.Concurrency != 1 {
-					t.Errorf(
-						"Concurrency = %d, want 1",
-						cfg.Concurrency,
-					)
-				}
 				if cfg.ShutdownTimeout != "30s" {
 					t.Errorf(
 						"ShutdownTimeout = %q, want %q",
@@ -365,9 +352,6 @@ func TestApplyDefaults(t *testing.T) {
 	if cfg.Address != ":8080" {
 		t.Errorf("Address = %q, want %q", cfg.Address, ":8080")
 	}
-	if cfg.Concurrency != 1 {
-		t.Errorf("Concurrency = %d, want 1", cfg.Concurrency)
-	}
 	if cfg.ShutdownTimeout != "30s" {
 		t.Errorf(
 			"ShutdownTimeout = %q, want %q",
@@ -379,7 +363,6 @@ func TestApplyDefaults(t *testing.T) {
 func TestApplyDefaults_NoOverwrite(t *testing.T) {
 	cfg := &Config{
 		Address:         ":9999",
-		Concurrency:     5,
 		ShutdownTimeout: "120s",
 	}
 	cfg.ApplyDefaults()
@@ -387,9 +370,6 @@ func TestApplyDefaults_NoOverwrite(t *testing.T) {
 	if cfg.Address != ":9999" {
 		t.Errorf("Address = %q, want %q", cfg.Address, ":9999")
 	}
-	if cfg.Concurrency != 5 {
-		t.Errorf("Concurrency = %d, want 5", cfg.Concurrency)
-	}
 	if cfg.ShutdownTimeout != "120s" {
 		t.Errorf(
 			"ShutdownTimeout = %q, want %q",