refactor: consolidate python/tests/ into tests/ directory

Move all Python test files from python/tests/ to the top-level tests/
directory to match the project's CONTRIBUTING.md guidelines. Update
sys.path inserts and template path references to reflect the new
location.

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

tests/conftest.py

@@ -0,0 +1,42 @@
+"""
+Test configuration for python/tests.
+
+Sets up sys.modules stubs for heavy KiCAD modules (pcbnew, skip) before any
+test module can trigger their import, preventing crashes on systems where the
+real KiCAD environment is not fully initialised for testing.
+"""
+
+import sys
+import types
+from unittest.mock import MagicMock
+
+# ---------------------------------------------------------------------------
+# pcbnew stub — kicad_interface.py accesses pcbnew.__file__ and
+# pcbnew.GetBuildVersion() at module level.  Use MagicMock so that any
+# attribute access (pcbnew.BOARD, pcbnew.PCB_TRACK, …) returns a mock
+# rather than raising AttributeError.
+# ---------------------------------------------------------------------------
+_pcbnew = MagicMock(name="pcbnew")
+_pcbnew.__file__ = "/fake/pcbnew.cpython-313-x86_64-linux-gnu.so"
+_pcbnew.__name__ = "pcbnew"
+_pcbnew.__spec__ = None
+_pcbnew.GetBuildVersion.return_value = "9.0.0-stub"
+sys.modules["pcbnew"] = _pcbnew
+
+# ---------------------------------------------------------------------------
+# Stub: skip  (kicad-skip — use real module if available, stub otherwise)
+# ---------------------------------------------------------------------------
+try:
+    import skip as _skip_test  # noqa: F401 — try importing real skip
+except ImportError:
+    skip_mod = types.ModuleType("skip")
+
+    class _FakeSchematic:
+        """Minimal stand-in for skip.Schematic used in PinLocator cache."""
+
+        def __init__(self, path: str):
+            self.path = path
+            self.symbol = []
+
+    skip_mod.Schematic = _FakeSchematic  # type: ignore[attr-defined]
+    sys.modules["skip"] = skip_mod