Render mermaid diagram per risk assessment scope

Each scope card now shows a flowchart of its nodes, processes, and
threats, with a distinct shape per type: stadium for entities,
hexagon for boundaries, rectangle for assets, cylinder for data, and
a red hexagon for threats attached via dashed edges to their process
target. The Mermaid source is built on the backend and exposed as a
new `mermaid` field on RiskAssessmentScope; the frontend just renders
it via @probo/ui's MermaidDiagram and shows a copy button + legend.

Signed-off-by: Sacha Al Himdani <sacha@getprobo.com>

pkg/coredata/risk_assessment_node.go

@@ -106,6 +106,45 @@ WHERE
 	return nil
 }
 
+func (ns *RiskAssessmentNodes) LoadAllByRiskAssessmentScopeID(
+	ctx context.Context,
+	conn pg.Querier,
+	scope Scoper,
+	riskAssessmentScopeID gid.GID,
+) error {
+	q := `
+SELECT
+	id,
+	organization_id,
+	risk_assessment_scope_id,
+	node_type,
+	name,
+	created_at,
+	updated_at
+FROM
+	risk_assessment_nodes
+WHERE
+	%s
+	AND risk_assessment_scope_id = @risk_assessment_scope_id
+ORDER BY
+	created_at ASC, id ASC
+`
+	q = fmt.Sprintf(q, scope.SQLFragment())
+	args := pgx.NamedArgs{"risk_assessment_scope_id": riskAssessmentScopeID}
+	maps.Copy(args, scope.SQLArguments())
+
+	rows, err := conn.Query(ctx, q, args)
+	if err != nil {
+		return fmt.Errorf("cannot query risk assessment nodes: %w", err)
+	}
+	results, err := pgx.CollectRows(rows, pgx.RowToAddrOfStructByName[RiskAssessmentNode])
+	if err != nil {
+		return fmt.Errorf("cannot collect risk assessment nodes: %w", err)
+	}
+	*ns = results
+	return nil
+}
+
 func (ns *RiskAssessmentNodes) CountByRiskAssessmentScopeID(
 	ctx context.Context,
 	conn pg.Querier,