Add Codex websocket header defaults

internal/config/config.go

@@ -90,6 +90,10 @@ type Config struct {
 	// Codex defines a list of Codex API key configurations as specified in the YAML configuration file.
 	CodexKey []CodexKey `yaml:"codex-api-key" json:"codex-api-key"`
 
+	// CodexHeaderDefaults configures fallback headers for Codex OAuth model requests.
+	// These are used only when the client does not send its own headers.
+	CodexHeaderDefaults CodexHeaderDefaults `yaml:"codex-header-defaults" json:"codex-header-defaults"`
+
 	// ClaudeKey defines a list of Claude API key configurations as specified in the YAML configuration file.
 	ClaudeKey []ClaudeKey `yaml:"claude-api-key" json:"claude-api-key"`
 
@@ -133,6 +137,14 @@ type ClaudeHeaderDefaults struct {
 	Timeout        string `yaml:"timeout" json:"timeout"`
 }
 
+// CodexHeaderDefaults configures fallback header values injected into Codex
+// model requests for OAuth/file-backed auth when the client omits them.
+// UserAgent applies to HTTP and websocket requests; BetaFeatures only applies to websockets.
+type CodexHeaderDefaults struct {
+	UserAgent    string `yaml:"user-agent" json:"user-agent"`
+	BetaFeatures string `yaml:"beta-features" json:"beta-features"`
+}
+
 // TLSConfig holds HTTPS server settings.
 type TLSConfig struct {
 	// Enable toggles HTTPS server mode.
@@ -615,6 +627,9 @@ func LoadConfigOptional(configFile string, optional bool) (*Config, error) {
 	// Sanitize Codex keys: drop entries without base-url
 	cfg.SanitizeCodexKeys()
 
+	// Sanitize Codex header defaults.
+	cfg.SanitizeCodexHeaderDefaults()
+
 	// Sanitize Claude key headers
 	cfg.SanitizeClaudeKeys()
 
@@ -704,6 +719,16 @@ func payloadRawString(value any) ([]byte, bool) {
 	}
 }
 
+// SanitizeCodexHeaderDefaults trims surrounding whitespace from the
+// configured Codex header fallback values.
+func (cfg *Config) SanitizeCodexHeaderDefaults() {
+	if cfg == nil {
+		return
+	}
+	cfg.CodexHeaderDefaults.UserAgent = strings.TrimSpace(cfg.CodexHeaderDefaults.UserAgent)
+	cfg.CodexHeaderDefaults.BetaFeatures = strings.TrimSpace(cfg.CodexHeaderDefaults.BetaFeatures)
+}
+
 // SanitizeOAuthModelAlias normalizes and deduplicates global OAuth model name aliases.
 // It trims whitespace, normalizes channel keys to lower-case, drops empty entries,
 // allows multiple aliases per upstream name, and ensures aliases are unique within each channel.