feat(rate-limiting): Implement core rate limiting functionality with configuration, decision-making, metrics, middleware, and service registration

- Add RateLimitConfig for configuration management with YAML binding support.
- Introduce RateLimitDecision to encapsulate the result of rate limit checks.
- Implement RateLimitMetrics for OpenTelemetry metrics tracking.
- Create RateLimitMiddleware for enforcing rate limits on incoming requests.
- Develop RateLimitService to orchestrate instance and environment rate limit checks.
- Add RateLimitServiceCollectionExtensions for dependency injection registration.

datasets/reachability/ground-truth/basic/gt-0005/main.c

@@ -0,0 +1,31 @@
+// gt-0005: Recursive function with sink
+// Expected: REACHABLE (tier: executed)
+// Vulnerability: CWE-134 (Format String)
+
+#include <stdio.h>
+#include <string.h>
+
+char result[1024];
+
+void process_recursive(const char *input, int depth) {
+    if (depth <= 0 || strlen(input) == 0) {
+        return;
+    }
+    
+    // Vulnerable: format string in recursive context
+    sprintf(result + strlen(result), input);  // SINK: CWE-134
+    
+    // Recurse with modified input
+    process_recursive(input + 1, depth - 1);
+}
+
+int main(int argc, char *argv[]) {
+    result[0] = '\0';
+    
+    if (argc > 1) {
+        process_recursive(argv[1], 5);
+        printf("Result: %s\n", result);
+    }
+    
+    return 0;
+}