feat: add intelligent storage auto-detection as default

- Change default storage from 'memory' to 'auto' for smart environment detection
- Add 'auto' support to storage type validation and TypeScript types
- Browser: auto-selects OPFS → memory fallback
- Node.js: auto-selects filesystem → memory fallback
- Cloud: auto-detects S3/GCS/R2 → disk → memory fallback
- Eliminates need for manual storage configuration in most cases

🤖 Generated with [Claude Code](https://claude.ai/code)

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

src/brainy.ts

@@ -1736,7 +1736,7 @@ export class Brainy<T = any> implements BrainyInterface<T> {
    */
   private async setupStorage(): Promise<StorageAdapter> {
     const storage = await createStorage({
-      type: this.config.storage?.type || 'memory',
+      type: this.config.storage?.type || 'auto',
       ...this.config.storage?.options
     })
     return storage
@@ -1790,8 +1790,8 @@ export class Brainy<T = any> implements BrainyInterface<T> {
    */
   private normalizeConfig(config?: BrainyConfig): Required<BrainyConfig> {
     // Validate storage configuration
-    if (config?.storage?.type && !['memory', 'filesystem', 'opfs', 'remote'].includes(config.storage.type)) {
-      throw new Error(`Invalid storage type: ${config.storage.type}. Must be one of: memory, filesystem, opfs, remote`)
+    if (config?.storage?.type && !['auto', 'memory', 'filesystem', 'opfs', 'remote', 's3', 'r2', 'gcs'].includes(config.storage.type)) {
+      throw new Error(`Invalid storage type: ${config.storage.type}. Must be one of: auto, memory, filesystem, opfs, remote, s3, r2, gcs`)
     }
 
     // Validate model configuration
@@ -1813,7 +1813,7 @@ export class Brainy<T = any> implements BrainyInterface<T> {
     }
 
     return {
-      storage: config?.storage || { type: 'memory' },
+      storage: config?.storage || { type: 'auto' },
       model: config?.model || { type: 'fast' },
       index: config?.index || {},
       cache: config?.cache ?? true,

src/types/brainy.types.ts

@@ -311,7 +311,7 @@ export type AggregateMetric =
 export interface BrainyConfig {
   // Storage configuration
   storage?: {
-    type: 'memory' | 'filesystem' | 's3' | 'r2' | 'opfs'
+    type: 'auto' | 'memory' | 'filesystem' | 's3' | 'r2' | 'opfs' | 'gcs'
     options?: any
   }