feat(simulation): add POST /<simulation_id>/clone endpoint (Task 6)

Implements SimulationManager.clone_simulation() and the corresponding
Flask route. The clone copies reddit_profiles.json, twitter_profiles.csv
and agent_profiles.json from the source simulation; does not copy
simulation_config.json; sets status=PROFILES_READY and records
parent_simulation_id. All 3 tests in test_simulation_clone.py pass.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/api/simulation.py

@@ -2875,3 +2875,31 @@ def patch_simulation_config_endpoint(simulation_id: str):
     except Exception as e:
         logger.error(f"patch_simulation_config failed: {e}")
         return jsonify({"success": False, "error": str(e), "traceback": traceback.format_exc()}), 500
+
+
+@simulation_bp.route('/<simulation_id>/clone', methods=['POST'])
+def clone_simulation(simulation_id: str):
+    """Clone a simulation: copy agent profiles, set status=profiles_ready."""
+    try:
+        data = request.get_json() or {}
+        project_id = data.get('project_id')
+        if not project_id:
+            return jsonify({"success": False, "error": "project_id is required"}), 400
+
+        manager = SimulationManager()
+        try:
+            new_state = manager.clone_simulation(simulation_id, project_id)
+        except ValueError as e:
+            return jsonify({"success": False, "error": str(e)}), 400
+
+        return jsonify({
+            "success": True,
+            "data": {
+                "new_simulation_id": new_state.simulation_id,
+                "parent_simulation_id": simulation_id,
+                "status": new_state.status.value,
+            }
+        })
+    except Exception as e:
+        logger.error(f"clone_simulation failed: {e}")
+        return jsonify({"success": False, "error": str(e)}), 500

backend/app/services/simulation_manager.py

@@ -635,6 +635,59 @@ class SimulationManager:
             os.remove(backup_file)
             raise
 
+    def clone_simulation(self, source_simulation_id: str, project_id: str) -> 'SimulationState':
+        """
+        Clone a simulation by copying its agent profiles to a new simulation.
+
+        The cloned simulation starts at PROFILES_READY status with config_generated=False.
+        Only profile files are copied; simulation_config.json is NOT copied.
+
+        Args:
+            source_simulation_id: ID of the simulation to clone
+            project_id: project ID for the new simulation
+
+        Returns:
+            New SimulationState
+
+        Raises:
+            ValueError: if source simulation not found or is in CREATED status
+        """
+        source_state = self.get_simulation(source_simulation_id)
+        if not source_state:
+            raise ValueError(f"Source simulation {source_simulation_id} not found")
+
+        if source_state.status == SimulationStatus.CREATED:
+            raise ValueError("Cannot clone a simulation in 'created' status (no profiles yet)")
+
+        import uuid
+        new_sim_id = f"sim_{uuid.uuid4().hex[:12]}"
+        new_state = SimulationState(
+            simulation_id=new_sim_id,
+            project_id=project_id,
+            graph_id=source_state.graph_id,
+            enable_twitter=source_state.enable_twitter,
+            enable_reddit=source_state.enable_reddit,
+            status=SimulationStatus.PROFILES_READY,
+            entities_count=source_state.entities_count,
+            profiles_count=source_state.profiles_count,
+            entity_types=list(source_state.entity_types),
+            config_generated=False,
+            parent_simulation_id=source_simulation_id,
+        )
+
+        src_dir = self._get_simulation_dir(source_simulation_id)
+        dst_dir = self._get_simulation_dir(new_sim_id)
+        os.makedirs(dst_dir, exist_ok=True)
+
+        for fname in ("reddit_profiles.json", "twitter_profiles.csv", "agent_profiles.json"):
+            src_file = os.path.join(src_dir, fname)
+            if os.path.exists(src_file):
+                shutil.copy2(src_file, os.path.join(dst_dir, fname))
+
+        self._save_simulation_state(new_state)
+        logger.info(f"Simulation cloned: {source_simulation_id} -> {new_sim_id}, project={project_id}")
+        return new_state
+
     def patch_simulation_config(self, simulation_id: str, fields: dict) -> dict:
         """
         Update global simulation config parameters (Fase B).

backend/tests/test_simulation_clone.py

@@ -0,0 +1,90 @@
+import json
+import pytest
+from pathlib import Path
+
+
+@pytest.fixture
+def app_client(tmp_path, monkeypatch):
+    from backend.app.services.simulation_manager import SimulationManager
+    monkeypatch.setattr(SimulationManager, 'SIMULATION_DATA_DIR', str(tmp_path))
+    from backend.app import create_app
+    app = create_app({'TESTING': True})
+    with app.test_client() as c:
+        yield c, tmp_path
+
+
+@pytest.fixture
+def completed_sim(app_client):
+    client, tmp_path = app_client
+    sim_id = "sim_src001"
+    sim_dir = tmp_path / sim_id
+    sim_dir.mkdir()
+    state = {
+        "simulation_id": sim_id, "project_id": "proj_src", "graph_id": "g1",
+        "status": "completed", "entities_count": 2, "profiles_count": 2,
+        "entity_types": [], "config_generated": True,
+        "parent_simulation_id": None, "graph_id_simulation": None,
+    }
+    (sim_dir / "state.json").write_text(json.dumps(state))
+    profiles = [
+        {"user_id": 0, "name": "Alice", "bio": "Bio A", "manually_edited": False},
+        {"user_id": 1, "name": "Bob", "bio": "Bio B", "manually_edited": True},
+    ]
+    (sim_dir / "reddit_profiles.json").write_text(json.dumps(profiles))
+    (sim_dir / "twitter_profiles.csv").write_text("user_id,name\n0,Alice\n1,Bob\n")
+    (sim_dir / "agent_profiles.json").write_text(json.dumps(profiles))
+    (sim_dir / "simulation_config.json").write_text(json.dumps({"time_config": {}}))
+    return client, tmp_path, sim_id
+
+
+def test_clone_creates_new_simulation(completed_sim):
+    """POST /api/simulation/<src_id>/clone returns 200, success=True, with new_simulation_id and parent_simulation_id."""
+    client, tmp_path, src_id = completed_sim
+    resp = client.post(
+        f'/api/simulation/{src_id}/clone',
+        json={"project_id": "proj_clone"},
+        content_type='application/json',
+    )
+    assert resp.status_code == 200
+    data = resp.get_json()
+    assert data["success"] is True
+    assert "new_simulation_id" in data["data"]
+    assert data["data"]["parent_simulation_id"] == src_id
+    assert data["data"]["new_simulation_id"] != src_id
+
+
+def test_clone_copies_profiles_not_config(completed_sim):
+    """Cloned sim dir has reddit_profiles.json + twitter_profiles.csv, but NOT simulation_config.json."""
+    client, tmp_path, src_id = completed_sim
+    resp = client.post(
+        f'/api/simulation/{src_id}/clone',
+        json={"project_id": "proj_clone"},
+        content_type='application/json',
+    )
+    assert resp.status_code == 200
+    data = resp.get_json()
+    new_id = data["data"]["new_simulation_id"]
+
+    new_dir = tmp_path / new_id
+    assert (new_dir / "reddit_profiles.json").exists(), "reddit_profiles.json should be copied"
+    assert (new_dir / "twitter_profiles.csv").exists(), "twitter_profiles.csv should be copied"
+    assert not (new_dir / "simulation_config.json").exists(), "simulation_config.json must NOT be copied"
+
+
+def test_clone_status_is_profiles_ready(completed_sim):
+    """Cloned sim state.json has status='profiles_ready' and correct parent_simulation_id."""
+    client, tmp_path, src_id = completed_sim
+    resp = client.post(
+        f'/api/simulation/{src_id}/clone',
+        json={"project_id": "proj_clone"},
+        content_type='application/json',
+    )
+    assert resp.status_code == 200
+    data = resp.get_json()
+    new_id = data["data"]["new_simulation_id"]
+
+    state_file = tmp_path / new_id / "state.json"
+    assert state_file.exists(), "state.json must be created for cloned simulation"
+    state = json.loads(state_file.read_text())
+    assert state["status"] == "profiles_ready"
+    assert state["parent_simulation_id"] == src_id