OPC # 0006: OPC Git Trunk-Based management

Co-authored-by: Copilot <copilot@github.com>

ControlPlane.Core/Models/ConformanceModels.cs

@@ -0,0 +1,28 @@
+namespace ControlPlane.Core.Models;
+
+public enum ConformanceViolation { OK, Missing, Diverged, Stale }
+public enum ConformanceSeverity  { OK, Info, Warning, Critical }
+
+/// <summary>
+/// The conformance state of one branch in the TBD ladder relative to its upstream source.
+/// </summary>
+public record BranchConformanceCheck(
+    string Branch,
+    string? SourceBranch,   // the upstream branch this is derived from (null for trunk)
+    ConformanceViolation Violation,
+    ConformanceSeverity Severity,
+    string Detail,
+    int AheadOfSource,      // commits this branch has that source doesn't — diverged
+    int BehindSource,       // commits source has that this branch doesn't — pending promotion
+    string? FixSha          // source tip SHA — used when resetting to fix divergence
+);
+
+/// <summary>
+/// Full TBD conformance report for a single repository.
+/// IsConformant = no Diverged or Missing violations exist.
+/// </summary>
+public record ConformanceReport(
+    string Repo,
+    bool IsConformant,
+    BranchConformanceCheck[] Checks
+);