feat: Implement Runtime Facts ingestion service and NDJSON reader

- Added RuntimeFactsNdjsonReader for reading NDJSON formatted runtime facts.
- Introduced IRuntimeFactsIngestionService interface and its implementation.
- Enhanced Program.cs to register new services and endpoints for runtime facts.
- Updated CallgraphIngestionService to include CAS URI in stored artifacts.
- Created RuntimeFactsValidationException for validation errors during ingestion.
- Added tests for RuntimeFactsIngestionService and RuntimeFactsNdjsonReader.
- Implemented SignalsSealedModeMonitor for compliance checks in sealed mode.
- Updated project dependencies for testing utilities.

src/Cli/StellaOps.Cli/Services/Models/Ruby/RubyPackageArtifactModel.cs

@@ -0,0 +1,28 @@
+using System.Collections.Generic;
+using System.Text.Json.Serialization;
+
+namespace StellaOps.Cli.Services.Models.Ruby;
+
+internal sealed record RubyPackageArtifactModel(
+    [property: JsonPropertyName("id")] string Id,
+    [property: JsonPropertyName("name")] string Name,
+    [property: JsonPropertyName("version")] string? Version,
+    [property: JsonPropertyName("source")] string? Source,
+    [property: JsonPropertyName("platform")] string? Platform,
+    [property: JsonPropertyName("groups")] IReadOnlyList<string>? Groups,
+    [property: JsonPropertyName("declaredOnly")] bool? DeclaredOnly,
+    [property: JsonPropertyName("runtimeUsed")] bool? RuntimeUsed,
+    [property: JsonPropertyName("provenance")] RubyPackageProvenance? Provenance,
+    [property: JsonPropertyName("runtime")] RubyPackageRuntime? Runtime,
+    [property: JsonPropertyName("metadata")] IDictionary<string, string?>? Metadata);
+
+internal sealed record RubyPackageProvenance(
+    [property: JsonPropertyName("source")] string? Source,
+    [property: JsonPropertyName("lockfile")] string? Lockfile,
+    [property: JsonPropertyName("locator")] string? Locator);
+
+internal sealed record RubyPackageRuntime(
+    [property: JsonPropertyName("entrypoints")] IReadOnlyList<string>? Entrypoints,
+    [property: JsonPropertyName("files")] IReadOnlyList<string>? Files,
+    [property: JsonPropertyName("reasons")] IReadOnlyList<string>? Reasons);
+