Add inline DSSE provenance documentation and Mongo schema

- Introduced a new document outlining the inline DSSE provenance for SBOM, VEX, scan, and derived events.
- Defined the Mongo schema for event patches, including key fields for provenance and trust verification.
- Documented the write path for ingesting provenance metadata and backfilling historical events.
- Created CI/CD snippets for uploading DSSE attestations and generating provenance metadata.
- Established Mongo indexes for efficient provenance queries and provided query recipes for various use cases.
- Outlined policy gates for managing VEX decisions based on provenance verification.
- Included UI nudges for displaying provenance information and implementation tasks for future enhancements.

---

Implement reachability lattice and scoring model

- Developed a comprehensive document detailing the reachability lattice and scoring model.
- Defined core types for reachability states, evidence, and mitigations with corresponding C# models.
- Established a scoring policy with base score contributions from various evidence classes.
- Mapped reachability states to VEX gates and provided a clear overview of evidence sources.
- Documented the event graph schema for persisting reachability data in MongoDB.
- Outlined the integration of runtime probes for evidence collection and defined a roadmap for future tasks.

---

Introduce uncertainty states and entropy scoring

- Created a draft document for tracking uncertainty states and their impact on risk scoring.
- Defined core uncertainty states with associated entropy values and evidence requirements.
- Established a schema for storing uncertainty states alongside findings.
- Documented the risk score calculation incorporating uncertainty and its effect on final risk assessments.
- Provided policy guidelines for handling uncertainty in decision-making processes.
- Outlined UI guidelines for displaying uncertainty information and suggested remediation actions.

---

Add Ruby package inventory management

- Implemented Ruby package inventory management with corresponding data models and storage mechanisms.
- Created C# records for Ruby package inventory, artifacts, provenance, and runtime details.
- Developed a repository for managing Ruby package inventory documents in MongoDB.
- Implemented a service for storing and retrieving Ruby package inventories.
- Added unit tests for the Ruby package inventory store to ensure functionality and data integrity.

src/Scanner/StellaOps.Scanner.WebService/Contracts/RubyContracts.cs

@@ -0,0 +1,21 @@
+using System.Text.Json.Serialization;
+using StellaOps.Scanner.Core.Contracts;
+
+namespace StellaOps.Scanner.WebService.Contracts;
+
+public sealed record RubyPackagesResponse
+{
+    [JsonPropertyName("scanId")]
+    public string ScanId { get; init; } = string.Empty;
+
+    [JsonPropertyName("imageDigest")]
+    public string ImageDigest { get; init; } = string.Empty;
+
+    [JsonPropertyName("generatedAt")]
+    public DateTimeOffset GeneratedAt { get; init; }
+        = DateTimeOffset.UtcNow;
+
+    [JsonPropertyName("packages")]
+    public IReadOnlyList<RubyPackageArtifact> Packages { get; init; }
+        = Array.Empty<RubyPackageArtifact>();
+}