feat: add (experimental) fine-tuning support with TRL (#9088)

* feat: add fine-tuning endpoint

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

* feat(experimental): add fine-tuning endpoint and TRL support

This changeset defines new GRPC signatues for Fine tuning backends, and
add TRL backend as initial fine-tuning engine. This implementation also
supports exporting to GGUF and automatically importing it to LocalAI
after fine-tuning.

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

* commit TRL backend, stop by killing process

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

* move fine-tune to generic features

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

* add evals, reorder menu

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

* Fix tests

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

---------

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

backend/python/trl/test.py

@@ -0,0 +1,58 @@
+"""
+Test script for the TRL fine-tuning gRPC backend.
+"""
+import unittest
+import subprocess
+import time
+
+import grpc
+import backend_pb2
+import backend_pb2_grpc
+
+
+class TestBackendServicer(unittest.TestCase):
+    """Tests for the TRL fine-tuning gRPC service."""
+
+    def setUp(self):
+        self.service = subprocess.Popen(
+            ["python3", "backend.py", "--addr", "localhost:50051"]
+        )
+        time.sleep(10)
+
+    def tearDown(self):
+        self.service.kill()
+        self.service.wait()
+
+    def test_server_startup(self):
+        """Test that the server starts and responds to health checks."""
+        try:
+            self.setUp()
+            with grpc.insecure_channel("localhost:50051") as channel:
+                stub = backend_pb2_grpc.BackendStub(channel)
+                response = stub.Health(backend_pb2.HealthMessage())
+                self.assertEqual(response.message, b'OK')
+        except Exception as err:
+            print(err)
+            self.fail("Server failed to start")
+        finally:
+            self.tearDown()
+
+    def test_list_checkpoints_empty(self):
+        """Test listing checkpoints on a non-existent directory."""
+        try:
+            self.setUp()
+            with grpc.insecure_channel("localhost:50051") as channel:
+                stub = backend_pb2_grpc.BackendStub(channel)
+                response = stub.ListCheckpoints(
+                    backend_pb2.ListCheckpointsRequest(output_dir="/nonexistent")
+                )
+                self.assertEqual(len(response.checkpoints), 0)
+        except Exception as err:
+            print(err)
+            self.fail("ListCheckpoints service failed")
+        finally:
+            self.tearDown()
+
+
+if __name__ == '__main__':
+    unittest.main()