feat: implement async processing for data pipeline operations

Refactor the core data processing module to use asyncio for concurrent task execution, replacing the previous synchronous loop. This change introduces async/await patterns across the main handler and utility functions, enabling non-blocking I/O for database queries and external API calls. The update includes new async context managers for connection pooling and error handling, improving throughput under high load scenarios.

tests/async_io_test.rc

@@ -0,0 +1,44 @@
+int main() {
+    printf("=== Async I/O Tests ===\n");
+
+    printf("Test 1: Async file write\n");
+    int f = fopen("async_test.txt", "w");
+    if (f == 0) {
+        printf("ERROR: Could not open file\n");
+        return 1;
+    }
+    int write_handle = async_fwrite(f, "Hello from async I/O!", 21);
+    printf("Write started, handle: %d\n", write_handle);
+    int result = async_wait(write_handle);
+    printf("Write completed, bytes written: %d\n", result);
+    fclose(f);
+    printf("PASS: Async write works\n");
+
+    printf("Test 2: Async file read\n");
+    f = fopen("async_test.txt", "r");
+    if (f == 0) {
+        printf("ERROR: Could not open file\n");
+        return 1;
+    }
+    int buffer[256];
+    int read_handle = async_fread(f, &buffer, 256);
+    printf("Read started, handle: %d\n", read_handle);
+
+    printf("Polling for completion...\n");
+    while (async_poll(read_handle) == 0) {
+        printf(".");
+    }
+    printf("\nRead complete!\n");
+
+    result = async_result(read_handle);
+    printf("Bytes read: %d\n", result);
+    fclose(f);
+    printf("PASS: Async read works\n");
+
+    printf("Test 3: Cleanup\n");
+    fremove("async_test.txt");
+    printf("PASS: File removed\n");
+
+    printf("\n=== All Async I/O Tests Completed ===\n");
+    return 0;
+}