fix: create_schematic now respects the path parameter

Previously the path argument to create_schematic() was accepted by the
tool schema but silently ignored in SchematicManager.create_schematic()
(python/commands/schematic.py). The schematic file was always written
using only the bare filename, resolving to the MCP server's working
directory.

On systems where that directory is not writable (e.g. Program Files,
OneDrive-synced folders) this caused:
  [Errno 13] Permission denied: 'myproject.kicad_sch'

Fix:
- Add path: Optional[str] = None parameter to SchematicManager.create_schematic()
- Compute output_path as os.path.join(path, base_name) when path is given
- Forward the resolved path from _handle_create_schematic() into create_schematic()

Tests: added tests/test_create_schematic_path.py with three unit tests
covering: path respected, no-path fallback, and no double-suffix on .kicad_sch names.

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

tests/test_create_schematic_path.py

@@ -0,0 +1,89 @@
+"""
+Unit tests for create_schematic path parameter bug fix.
+
+Verifies that create_schematic respects the `path` argument and writes
+the schematic file to the correct directory instead of the process cwd.
+"""
+
+import os
+import sys
+import importlib.util
+import tempfile
+from unittest.mock import patch, MagicMock
+
+# pcbnew and skip are only available inside KiCAD — stub them so the
+# schematic module can be imported in a plain Python environment.
+sys.modules.setdefault("pcbnew", MagicMock())
+sys.modules.setdefault("skip", MagicMock())
+
+# Import the module directly (bypasses python/commands/__init__.py which
+# would otherwise pull in board/component commands that also need pcbnew).
+_spec = importlib.util.spec_from_file_location(
+    "schematic_module",
+    os.path.join(os.path.dirname(__file__), "..", "python", "commands", "schematic.py"),
+)
+_mod = importlib.util.module_from_spec(_spec)
+_spec.loader.exec_module(_mod)
+SchematicManager = _mod.SchematicManager
+
+_OPEN_MOCK = MagicMock(return_value=MagicMock(
+    __enter__=MagicMock(return_value=MagicMock(
+        read=MagicMock(return_value="(uuid 00000000-0000-0000-0000-000000000000)")
+    )),
+    __exit__=MagicMock(return_value=False),
+))
+
+
+def test_create_schematic_uses_path_argument():
+    """
+    create_schematic should write the .kicad_sch file inside `path`
+    when that argument is provided, not in the process working directory.
+    """
+    with tempfile.TemporaryDirectory() as tmpdir:
+        with patch.object(_mod, "Schematic") as mock_sch_cls, \
+             patch("shutil.copy"), \
+             patch("os.path.exists", return_value=True), \
+             patch("builtins.open", _OPEN_MOCK):
+            mock_sch_cls.return_value = MagicMock()
+
+            SchematicManager.create_schematic("myschematic", path=tmpdir)
+
+            used_path = mock_sch_cls.call_args[0][0]
+            assert used_path.startswith(tmpdir), (
+                f"Expected path inside {tmpdir!r}, got {used_path!r}"
+            )
+            assert used_path.endswith("myschematic.kicad_sch")
+
+
+def test_create_schematic_without_path_uses_relative():
+    """
+    When no path is given, behaviour is unchanged — file goes to cwd-relative name.
+    """
+    with patch.object(_mod, "Schematic") as mock_sch_cls, \
+         patch("shutil.copy"), \
+         patch("os.path.exists", return_value=True), \
+         patch("builtins.open", _OPEN_MOCK):
+        mock_sch_cls.return_value = MagicMock()
+
+        SchematicManager.create_schematic("myschematic")
+
+        used_path = mock_sch_cls.call_args[0][0]
+        assert used_path == "myschematic.kicad_sch"
+
+
+def test_create_schematic_accepts_full_sch_filename():
+    """
+    If name already ends with .kicad_sch, it should not double the suffix.
+    """
+    with tempfile.TemporaryDirectory() as tmpdir:
+        with patch.object(_mod, "Schematic") as mock_sch_cls, \
+             patch("shutil.copy"), \
+             patch("os.path.exists", return_value=True), \
+             patch("builtins.open", _OPEN_MOCK):
+            mock_sch_cls.return_value = MagicMock()
+
+            SchematicManager.create_schematic("myschematic.kicad_sch", path=tmpdir)
+
+            used_path = mock_sch_cls.call_args[0][0]
+            assert used_path.endswith("myschematic.kicad_sch")
+            assert "myschematic.kicad_sch.kicad_sch" not in used_path