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/api/handlers/management/config_lists.go

@@ -464,6 +464,7 @@ func (h *Handler) PatchOpenAICompat(c *gin.Context) {
 	type openAICompatPatch struct {
 		Name          *string                             `json:"name"`
 		Prefix        *string                             `json:"prefix"`
+		Disabled      *bool                               `json:"disabled"`
 		BaseURL       *string                             `json:"base-url"`
 		APIKeyEntries *[]config.OpenAICompatibilityAPIKey `json:"api-key-entries"`
 		Models        *[]config.OpenAICompatibilityModel  `json:"models"`
@@ -506,6 +507,9 @@ func (h *Handler) PatchOpenAICompat(c *gin.Context) {
 	if body.Value.Prefix != nil {
 		entry.Prefix = strings.TrimSpace(*body.Value.Prefix)
 	}
+	if body.Value.Disabled != nil {
+		entry.Disabled = *body.Value.Disabled
+	}
 	if body.Value.BaseURL != nil {
 		trimmed := strings.TrimSpace(*body.Value.BaseURL)
 		if trimmed == "" {