feat(types): add HOP entity tracking types (bd-7pwh)

- Add EntityRef type for structured entity references with URI support
- Add Creator field to Issue for tracking who created work
- Add Validation type and Validations field for proof-of-stake approvals
- Fix RemoveDependency FK violation on external deps (bd-a3sj)
- Include all new fields in content hash computation
- Full test coverage for all new types

🤝 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

internal/storage/sqlite/dependencies.go

@@ -221,8 +221,13 @@ func (s *SQLiteStorage) RemoveDependency(ctx context.Context, issueID, dependsOn
 			return fmt.Errorf("failed to record event: %w", err)
 		}
 
-		// Mark both issues as dirty for incremental export
-		if err := markIssuesDirtyTx(ctx, tx, []string{issueID, dependsOnID}); err != nil {
+		// Mark issues as dirty for incremental export
+		// For external refs, only mark the source issue (target doesn't exist locally)
+		issueIDsToMark := []string{issueID}
+		if !strings.HasPrefix(dependsOnID, "external:") {
+			issueIDsToMark = append(issueIDsToMark, dependsOnID)
+		}
+		if err := markIssuesDirtyTx(ctx, tx, issueIDsToMark); err != nil {
 			return wrapDBError("mark issues dirty after removing dependency", err)
 		}
 

internal/storage/sqlite/dependencies_test.go

@@ -1610,3 +1610,50 @@ func TestDetectCycles_RelatesTypeAllowsBidirectionalWithoutCycleReport(t *testin
 		t.Error("Expected B to relate-to A")
 	}
 }
+
+// TestRemoveDependencyExternal verifies that removing an external dependency
+// doesn't cause FK violation (bd-a3sj). External refs like external:project:capability
+// don't exist in the issues table, so we must not mark them as dirty.
+func TestRemoveDependencyExternal(t *testing.T) {
+	store, cleanup := setupTestDB(t)
+	defer cleanup()
+
+	ctx := context.Background()
+
+	// Create an issue
+	issue := &types.Issue{
+		Title:     "Issue with external dep",
+		Status:    types.StatusOpen,
+		Priority:  1,
+		IssueType: types.TypeTask,
+	}
+	if err := store.CreateIssue(ctx, issue, "test-user"); err != nil {
+		t.Fatalf("CreateIssue failed: %v", err)
+	}
+
+	// Add an external dependency
+	externalRef := "external:other-project:some-capability"
+	dep := &types.Dependency{
+		IssueID:     issue.ID,
+		DependsOnID: externalRef,
+		Type:        types.DepBlocks,
+	}
+	if err := store.AddDependency(ctx, dep, "test-user"); err != nil {
+		t.Fatalf("AddDependency failed: %v", err)
+	}
+
+	// This should NOT cause FK violation (the bug was marking external ref as dirty)
+	err := store.RemoveDependency(ctx, issue.ID, externalRef, "test-user")
+	if err != nil {
+		t.Fatalf("RemoveDependency on external ref should succeed, got: %v", err)
+	}
+
+	// Verify dependency was actually removed
+	deps, err := store.GetDependencyRecords(ctx, issue.ID)
+	if err != nil {
+		t.Fatalf("GetDependencyRecords failed: %v", err)
+	}
+	if len(deps) != 0 {
+		t.Errorf("Expected 0 dependencies after removal, got %d", len(deps))
+	}
+}