feat(scenario): step output, getStepOutput helper, export/import MCP tools, doc restructure

- add output column to ScenarioRunStepEntity; exec step return value is JSON-serialised and stored
- expose helpers.getStepOutput(order) in exec code; negative order is relative to current step
- add get_scenario_run, wait_for_scenario_run, export_scenario, import_scenario MCP tools
- move Architecture, Key descriptors, MCP tools, Scenario, Development docs to docs/
- delete CONTRIBUTING.md (replaced by docs/development.md)

test/scenario.controller.spec.ts

@@ -106,7 +106,9 @@ describe("ScenarioController", () => {
       const res = await request(app.getHttpServer())
         .get("/scenarios?orderBy=name&orderDir=ASC")
         .expect(200);
-      const names: string[] = res.body.data.map((s: { name: string }) => s.name);
+      const names: string[] = res.body.data.map(
+        (s: { name: string }) => s.name,
+      );
       expect(names).toEqual([...names].sort());
     });
 
@@ -114,7 +116,9 @@ describe("ScenarioController", () => {
       const res = await request(app.getHttpServer())
         .get("/scenarios?orderBy=name&orderDir=DESC")
         .expect(200);
-      const names: string[] = res.body.data.map((s: { name: string }) => s.name);
+      const names: string[] = res.body.data.map(
+        (s: { name: string }) => s.name,
+      );
       expect(names).toEqual([...names].sort().reverse());
     });
 
@@ -336,7 +340,9 @@ describe("ScenarioController", () => {
       expect(Array.isArray(res.body.stepRuns)).toBe(true);
       expect(res.body.stepRuns).toHaveLength(3);
 
-      const statuses = res.body.stepRuns.map((s: { status: string }) => s.status);
+      const statuses = res.body.stepRuns.map(
+        (s: { status: string }) => s.status,
+      );
       expect(statuses[0]).toBe("pending");
       expect(statuses[1]).toBe("waiting");
       expect(statuses[2]).toBe("waiting");