feat(config): add support for disabling OpenAI compatibility providers

- Introduced a `Disabled` flag to OpenAI compatibility configurations.
- Updated routing, auth selection, and API handling logic to respect the `Disabled` state.
- Extended relevant APIs, YAML configurations, and data structures to include the `Disabled` field.
- Adjusted all relevant loops and filters to skip disabled providers.

Closes: #3060 #3059 #2977

internal/runtime/executor/openai_compat_executor.go

@@ -378,6 +378,9 @@ func (e *OpenAICompatExecutor) resolveCompatConfig(auth *cliproxyauth.Auth) *con
 	}
 	for i := range e.cfg.OpenAICompatibility {
 		compat := &e.cfg.OpenAICompatibility[i]
+		if compat.Disabled {
+			continue
+		}
 		for _, candidate := range candidates {
 			if candidate != "" && strings.EqualFold(strings.TrimSpace(candidate), compat.Name) {
 				return compat