Reorganize src/ directory into feature/domain-based structure

Restructure flat src/ directory (17 files) into organized folders:

Structure:
- src/core/ - Main API (rondevu.ts, offer-pool.ts, types.ts, index.ts)
- src/connections/ - WebRTC connections (base.ts, offerer.ts, answerer.ts, config.ts, events.ts)
- src/api/ - HTTP layer (client.ts, batcher.ts)
- src/crypto/ - Crypto adapters (adapter.ts, node.ts, web.ts)
- src/utils/ - Utilities (async-lock.ts, exponential-backoff.ts, message-buffer.ts)

Changes:
- Move all 17 files to appropriate feature folders
- Update all import paths to reflect new structure
- Update package.json main/types to point to dist/core/index.js
- Preserve git history with git mv

Benefits:
- Clear separation of concerns
- Easier navigation and maintenance
- Better scalability for future features
- Logical grouping of related files

🤖 Generated with Claude Code

src/api/batcher.ts

@@ -0,0 +1,157 @@
+/**
+ * RPC Batcher - Throttles and batches RPC requests to reduce HTTP overhead
+ */
+
+export interface BatcherOptions {
+    /**
+     * Maximum number of requests to batch together
+     * Default: 10
+     */
+    maxBatchSize?: number
+
+    /**
+     * Maximum time to wait before sending a batch (ms)
+     * Default: 50ms
+     */
+    maxWaitTime?: number
+
+    /**
+     * Minimum time between batches (ms)
+     * Default: 10ms
+     */
+    throttleInterval?: number
+}
+
+interface QueuedRequest {
+    request: any
+    resolve: (value: any) => void
+    reject: (error: Error) => void
+}
+
+/**
+ * Batches and throttles RPC requests to optimize network usage
+ *
+ * @example
+ * ```typescript
+ * const batcher = new RpcBatcher(
+ *   (requests) => api.rpcBatch(requests),
+ *   { maxBatchSize: 10, maxWaitTime: 50 }
+ * )
+ *
+ * // These will be batched together if called within maxWaitTime
+ * const result1 = await batcher.add(request1)
+ * const result2 = await batcher.add(request2)
+ * const result3 = await batcher.add(request3)
+ * ```
+ */
+export class RpcBatcher {
+    private queue: QueuedRequest[] = []
+    private batchTimeout: ReturnType<typeof setTimeout> | null = null
+    private lastBatchTime: number = 0
+    private options: Required<BatcherOptions>
+    private sendBatch: (requests: any[]) => Promise<any[]>
+
+    constructor(
+        sendBatch: (requests: any[]) => Promise<any[]>,
+        options?: BatcherOptions
+    ) {
+        this.sendBatch = sendBatch
+        this.options = {
+            maxBatchSize: options?.maxBatchSize ?? 10,
+            maxWaitTime: options?.maxWaitTime ?? 50,
+            throttleInterval: options?.throttleInterval ?? 10,
+        }
+    }
+
+    /**
+     * Add an RPC request to the batch queue
+     * Returns a promise that resolves when the request completes
+     */
+    async add(request: any): Promise<any> {
+        return new Promise((resolve, reject) => {
+            this.queue.push({ request, resolve, reject })
+
+            // Send immediately if batch is full
+            if (this.queue.length >= this.options.maxBatchSize) {
+                this.flush()
+                return
+            }
+
+            // Schedule batch if not already scheduled
+            if (!this.batchTimeout) {
+                this.batchTimeout = setTimeout(() => {
+                    this.flush()
+                }, this.options.maxWaitTime)
+            }
+        })
+    }
+
+    /**
+     * Flush the queue immediately
+     */
+    async flush(): Promise<void> {
+        // Clear timeout if set
+        if (this.batchTimeout) {
+            clearTimeout(this.batchTimeout)
+            this.batchTimeout = null
+        }
+
+        // Nothing to flush
+        if (this.queue.length === 0) {
+            return
+        }
+
+        // Throttle: wait if we sent a batch too recently
+        const now = Date.now()
+        const timeSinceLastBatch = now - this.lastBatchTime
+        if (timeSinceLastBatch < this.options.throttleInterval) {
+            const waitTime = this.options.throttleInterval - timeSinceLastBatch
+            await new Promise(resolve => setTimeout(resolve, waitTime))
+        }
+
+        // Extract requests from queue
+        const batch = this.queue.splice(0, this.options.maxBatchSize)
+        const requests = batch.map(item => item.request)
+
+        this.lastBatchTime = Date.now()
+
+        try {
+            // Send batch request
+            const results = await this.sendBatch(requests)
+
+            // Resolve individual promises
+            for (let i = 0; i < batch.length; i++) {
+                batch[i].resolve(results[i])
+            }
+        } catch (error) {
+            // Reject all promises in batch
+            for (const item of batch) {
+                item.reject(error as Error)
+            }
+        }
+    }
+
+    /**
+     * Get current queue size
+     */
+    getQueueSize(): number {
+        return this.queue.length
+    }
+
+    /**
+     * Clear the queue without sending
+     */
+    clear(): void {
+        if (this.batchTimeout) {
+            clearTimeout(this.batchTimeout)
+            this.batchTimeout = null
+        }
+
+        // Reject all pending requests
+        for (const item of this.queue) {
+            item.reject(new Error('Batch queue cleared'))
+        }
+
+        this.queue = []
+    }
+}