OPC # 0006: OPC Git Trunk-Based management

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

ControlPlane.Api/Services/ReleaseService.cs

@@ -51,7 +51,12 @@ public class ReleaseService(
             return blocked;
         }
 
-        var record = await history.CreateReleaseAsync(targetEnv, ImageName);
+        // Resolve the Clarity branch for this environment and stamp the HEAD SHA
+        // before creating the record so we capture "what was deployed" accurately.
+        var branch    = targetEnv switch { "fdev" => "develop", "staging" => "staging", "uat" => "uat", _ => "main" };
+        var currentSha = promotions.GetBranchTipSha("Clarity", branch);
+
+        var record = await history.CreateReleaseAsync(targetEnv, ImageName, currentSha);
 
         try
         {
@@ -183,9 +188,16 @@ public class ReleaseService(
         }
         finally
         {
-            // Stamp OPC ticket numbers from recent commits on the target branch.
-            var branch = targetEnv switch { "fdev" => "develop", "staging" => "staging", "uat" => "uat", _ => "main" };
-            try   { record.OpcNumbers = await promotions.ExtractOpcNumbersAsync("Clarity", branch, 50, ct); }
+            // Stamp the exact OPC ticket numbers introduced by this release:
+            // diff from previous release's SHA to this release's SHA on the Clarity branch.
+            try
+            {
+                var prev = await history.GetLastSuccessfulReleaseForEnvAsync(targetEnv);
+                // Exclude the current (in-flight) record — it's not succeeded yet
+                var prevSha = prev?.Id == record.Id ? null : prev?.CommitSha;
+                if (currentSha is not null)
+                    record.OpcNumbers = await promotions.ExtractOpcNumbersDeltaAsync("Clarity", currentSha, prevSha, ct);
+            }
             catch { /* git not configured — continue without OPC stamp */ }
 
             await history.UpdateReleaseAsync(record);