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.

src/Cli/StellaOps.Cli/Output/OutputFormat.cs

@@ -3,6 +3,7 @@ namespace StellaOps.Cli.Output;
 /// <summary>
 /// Output format for CLI commands.
 /// Per CLI-CORE-41-001, supports json/yaml/table formats.
+/// Task SDIFF-BIN-030: Added SARIF format for CI/CD integration.
 /// </summary>
 public enum OutputFormat
 {
@@ -13,5 +14,8 @@ public enum OutputFormat
     Json,
 
     /// <summary>YAML format for configuration/scripting.</summary>
-    Yaml
+    Yaml,
+
+    /// <summary>SARIF 2.1.0 format for CI/CD integration (GitHub, GitLab, Azure DevOps).</summary>
+    Sarif
 }