feat(pagination): add generic typed pagination with ordering to all list endpoints

- add PaginationQueryDto<TOrderBy> generic with orderBy and orderDir fields
- add SessionOrderBy, EnvironmentOrderBy, ScenarioOrderBy type aliases
- update session, environment, scenario services and controllers to use typed pagination
- update MCP list_sessions, list_environments, list_scenarios tools to expose orderBy/orderDir
- update tests for all list endpoints to cover page, limit, ordering, and invalid param rejection

test/mcp.controller.spec.ts

@@ -83,22 +83,26 @@ describe('McpController', () => {
   // ── list_sessions tool ─────────────────────────────────────────────────────
 
   describe('list_sessions', () => {
-    it('returns a result with text content containing a JSON array', async () => {
+    it('returns a paginated result with a data array', async () => {
       const { status, rpc } = await mcpCall('list_sessions');
       expect(status).toBe(200);
       const result = rpc.result as { content: { text: string }[] };
-      expect(Array.isArray(JSON.parse(result.content[0].text))).toBe(true);
+      const body = JSON.parse(result.content[0].text) as { data: unknown[]; total: number };
+      expect(Array.isArray(body.data)).toBe(true);
+      expect(typeof body.total).toBe('number');
     });
   });
 
   // ── list_environments tool ─────────────────────────────────────────────────
 
   describe('list_environments', () => {
-    it('returns a result with text content containing a JSON array', async () => {
+    it('returns a paginated result with a data array', async () => {
       const { status, rpc } = await mcpCall('list_environments');
       expect(status).toBe(200);
       const result = rpc.result as { content: { text: string }[] };
-      expect(Array.isArray(JSON.parse(result.content[0].text))).toBe(true);
+      const body = JSON.parse(result.content[0].text) as { data: unknown[]; total: number };
+      expect(Array.isArray(body.data)).toBe(true);
+      expect(typeof body.total).toBe('number');
     });
   });