feat(01-01): add provider types to types/index.ts

Add ProviderType union, ProviderConfig interface, and ProviderSettings
interface to support multi-provider API key management for Replicate
and fal.ai alongside existing Gemini support.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/types/index.ts

@@ -297,3 +297,18 @@ export interface NodeGroup {
   size: { width: number; height: number };
   locked?: boolean;
 }
+
+// Provider Types for multi-provider support
+export type ProviderType = "gemini" | "replicate" | "fal";
+
+export interface ProviderConfig {
+  id: ProviderType;
+  name: string;
+  enabled: boolean;
+  apiKey: string | null;
+  apiKeyEnvVar?: string;  // For providers using environment variables (e.g., Gemini)
+}
+
+export interface ProviderSettings {
+  providers: Record<ProviderType, ProviderConfig>;
+}