fix: include KiCad 10 Windows install paths in library auto-discovery

Fixes #245 — _find_kicad_footprint_dir() only listed the 9.0/8.0 Windows
install paths, so a Windows host with only KiCad 10 installed got None and
footprint auto-discovery found nothing. The same gap existed for symbols in
library_symbol.py and dynamic_symbol_loader.py.

- Add C:/Program Files/KiCad/10.0/share/kicad/{footprints,symbols} to the
  candidate lists (10.0 first, matching the existing newest-first order)
- Honor KICAD10_FOOTPRINT_DIR and KICAD10_SYMBOL_DIR env overrides alongside
  the existing 9/8 ones
- Regression tests in tests/test_kicad10_paths.py

python/commands/dynamic_symbol_loader.py

@@ -38,6 +38,7 @@ class DynamicSymbolLoader:
         possible_paths = [
             Path("/usr/share/kicad/symbols"),
             Path("/usr/local/share/kicad/symbols"),
+            Path("C:/Program Files/KiCad/10.0/share/kicad/symbols"),
             Path("C:/Program Files/KiCad/9.0/share/kicad/symbols"),
             Path("C:/Program Files/KiCad/8.0/share/kicad/symbols"),
             Path("/Applications/KiCad/KiCad.app/Contents/SharedSupport/symbols"),
@@ -477,8 +478,10 @@ class DynamicSymbolLoader:
             # Iterate over every top-level (property ...) block in the symbol
             search_pos = 0
             while True:
-                m = re.search(r'\(property\s+"([^"]+)"\s+"[^"]*"\s+\(at\s+([-\d.]+)\s+([-\d.]+)\s+([-\d.]+)\)',
-                              sym_block[search_pos:])
+                m = re.search(
+                    r'\(property\s+"([^"]+)"\s+"[^"]*"\s+\(at\s+([-\d.]+)\s+([-\d.]+)\s+([-\d.]+)\)',
+                    sym_block[search_pos:],
+                )
                 if not m:
                     break
                 abs_start = search_pos + m.start()
@@ -495,7 +498,7 @@ class DynamicSymbolLoader:
                     effects_str = self._extract_paren_block(prop_block, eff_pos)
                     # Strip (hide ...) sub-expressions — visibility will be set
                     # separately by the caller
-                    effects_str = re.sub(r'\s*\(hide\s+[^)]+\)', '', effects_str)
+                    effects_str = re.sub(r"\s*\(hide\s+[^)]+\)", "", effects_str)
                     effects_str = effects_str.strip()
                 else:
                     effects_str = "(effects (font (size 1.27 1.27)))"
@@ -556,14 +559,13 @@ class DynamicSymbolLoader:
         new_uuid = str(uuid.uuid4())
 
         # --- read property offsets from the already-injected lib_symbols block -----
-        lib_props = self._extract_lib_property_positions(
-            schematic_path, library_name, symbol_name
-        )
+        lib_props = self._extract_lib_property_positions(schematic_path, library_name, symbol_name)
 
         _DEFAULT_EFFECTS = "(effects (font (size 1.27 1.27)))"
 
-        def _prop_at(name: str, fallback_dx: float, fallback_dy: float,
-                     fallback_angle: float = 0) -> tuple:
+        def _prop_at(
+            name: str, fallback_dx: float, fallback_dy: float, fallback_angle: float = 0
+        ) -> tuple:
             """Return (abs_x, abs_y, text_angle, effects_str) for a property."""
             if name in lib_props:
                 dx, dy, text_ang, eff = lib_props[name]

python/commands/library.py

@@ -182,12 +182,15 @@ class LibraryManager:
         possible_paths = [
             "/usr/share/kicad/footprints",
             "/usr/local/share/kicad/footprints",
+            "C:/Program Files/KiCad/10.0/share/kicad/footprints",
             "C:/Program Files/KiCad/9.0/share/kicad/footprints",
             "C:/Program Files/KiCad/8.0/share/kicad/footprints",
             "/Applications/KiCad/KiCad.app/Contents/SharedSupport/footprints",
         ]
 
         # Also check environment variable
+        if "KICAD10_FOOTPRINT_DIR" in os.environ:
+            possible_paths.insert(0, os.environ["KICAD10_FOOTPRINT_DIR"])
         if "KICAD9_FOOTPRINT_DIR" in os.environ:
             possible_paths.insert(0, os.environ["KICAD9_FOOTPRINT_DIR"])
         if "KICAD8_FOOTPRINT_DIR" in os.environ:

python/commands/library_symbol.py

@@ -83,9 +83,7 @@ class SymbolLibraryManager:
                     logger.debug("Skipping unparseable library: %s", nickname)
             logger.info("Symbol cache warm-up complete (%d libraries)", len(self.libraries))
 
-        threading.Thread(
-            target=_warm, name="symbol-cache-warmup", daemon=True
-        ).start()
+        threading.Thread(target=_warm, name="symbol-cache-warmup", daemon=True).start()
 
     def _load_libraries(self) -> None:
         """Load libraries from sym-lib-table files"""
@@ -232,12 +230,15 @@ class SymbolLibraryManager:
         possible_paths = [
             "/usr/share/kicad/symbols",
             "/usr/local/share/kicad/symbols",
+            "C:/Program Files/KiCad/10.0/share/kicad/symbols",
             "C:/Program Files/KiCad/9.0/share/kicad/symbols",
             "C:/Program Files/KiCad/8.0/share/kicad/symbols",
             "/Applications/KiCad/KiCad.app/Contents/SharedSupport/symbols",
         ]
 
         # Check environment variable
+        if "KICAD10_SYMBOL_DIR" in os.environ:
+            possible_paths.insert(0, os.environ["KICAD10_SYMBOL_DIR"])
         if "KICAD9_SYMBOL_DIR" in os.environ:
             possible_paths.insert(0, os.environ["KICAD9_SYMBOL_DIR"])
         if "KICAD8_SYMBOL_DIR" in os.environ:
@@ -610,8 +611,10 @@ class SymbolLibraryCommands:
         # Patch (SER2RJ45): keep cache when project_path matches AND libraries were
         # actually loaded. Original early-return skipped rebuild even when the cache
         # was empty (e.g. first call after create_project, before sym-lib-table existed).
-        if (self.library_manager.project_path == project_path
-                and len(self.library_manager.libraries) > 0):
+        if (
+            self.library_manager.project_path == project_path
+            and len(self.library_manager.libraries) > 0
+        ):
             return
         logger.info(f"Rebuilding SymbolLibraryManager for project: {project_path}")
         self.library_manager = SymbolLibraryManager(project_path=project_path)

tests/test_kicad10_paths.py

@@ -0,0 +1,46 @@
+"""Regression tests for issue #245: KiCad 10 Windows install paths must be in
+the auto-discovery candidate lists (footprints and symbols), with env-var
+overrides for KiCad 10.
+"""
+
+import sys
+from pathlib import Path
+from unittest.mock import patch
+
+import pytest
+
+sys.path.insert(0, str(Path(__file__).parent.parent / "python"))
+
+from commands.library import LibraryManager  # noqa: E402
+from commands.library_symbol import SymbolLibraryManager  # noqa: E402
+
+K10_FOOTPRINTS = "C:/Program Files/KiCad/10.0/share/kicad/footprints"
+K10_SYMBOLS = "C:/Program Files/KiCad/10.0/share/kicad/symbols"
+
+
+@pytest.mark.unit
+class TestKicad10FootprintDir:
+    def test_k10_windows_path_is_discovered(self):
+        lm = LibraryManager.__new__(LibraryManager)
+        with patch("commands.library.os.path.isdir", side_effect=lambda p: p == K10_FOOTPRINTS):
+            assert lm._find_kicad_footprint_dir() == K10_FOOTPRINTS
+
+    def test_k10_env_override_wins(self, monkeypatch):
+        lm = LibraryManager.__new__(LibraryManager)
+        monkeypatch.setenv("KICAD10_FOOTPRINT_DIR", "/custom/k10/footprints")
+        with patch("commands.library.os.path.isdir", return_value=True):
+            assert lm._find_kicad_footprint_dir() == "/custom/k10/footprints"
+
+
+@pytest.mark.unit
+class TestKicad10SymbolDir:
+    def test_k10_windows_path_is_discovered(self):
+        sm = SymbolLibraryManager.__new__(SymbolLibraryManager)
+        with patch("commands.library_symbol.os.path.isdir", side_effect=lambda p: p == K10_SYMBOLS):
+            assert sm._find_kicad_symbol_dir() == K10_SYMBOLS
+
+    def test_k10_env_override_wins(self, monkeypatch):
+        sm = SymbolLibraryManager.__new__(SymbolLibraryManager)
+        monkeypatch.setenv("KICAD10_SYMBOL_DIR", "/custom/k10/symbols")
+        with patch("commands.library_symbol.os.path.isdir", return_value=True):
+            assert sm._find_kicad_symbol_dir() == "/custom/k10/symbols"