fix(dart): omit rootUri/rootPath (#2045) (#2051)

The Dart analysis server treats rootUri as an additional analysis root on top of
workspaceFolders, with no de-duplication, so on a monorepo root the whole tree is
analysed and the server burns CPU at idle. Always omit rootUri/rootPath and rely on
workspaceFolders alone.

test/solidlsp/test_initialize_params_root_uri.py

@@ -0,0 +1,39 @@
+# SPDX-License-Identifier: MIT
+
+import tempfile
+from pathlib import Path
+
+from solidlsp.initialize_params import DefaultInitializeParamsBuilder
+
+
+class _FakeLS:
+    # Windows: as_uri() rejects drive-less paths like "/tmp/..."
+    repository_root_path = str(Path(tempfile.mkdtemp(prefix="fake-project-")) / "root")
+
+    class config:
+        @staticmethod
+        def get_absolute_workspace_folders(root):
+            return [root]
+
+        @staticmethod
+        def get_absolute_additional_workspace_folders(root):
+            return []
+
+    custom_settings: dict = {}
+
+
+def test_default_builder_sets_root_uri():
+    builder = DefaultInitializeParamsBuilder(_FakeLS())
+    params = builder.build()
+    assert "rootUri" in params
+    assert "rootPath" in params
+
+
+def test_builder_sends_null_root_uri_when_disabled():
+    builder = DefaultInitializeParamsBuilder(_FakeLS(), set_root_uri=False)
+    params = builder.build()
+    # keys must be present (some servers reject an undefined rootUri); values are null
+    assert params["rootUri"] is None
+    assert params["rootPath"] is None
+    assert params["processId"] is not None
+    assert params["clientInfo"] == {"name": "Serena"}