chore: enable strict mypy checks and fix pre-commit mypy hook

Add type annotations to all previously untyped functions and remove 9
suppressed error codes (call-arg, assignment, return-value, operator,
has-type, dict-item, misc, list-item, annotation-unchecked) by fixing
the underlying type issues.

Add [[tool.mypy.overrides]] with ignore_missing_imports for KiCAD-specific
modules (pcbnew, sexpdata, skip, cairosvg, kipy, PIL) so the pre-commit
mypy hook passes in its isolated venv. Add types-requests and pytest to
additional_dependencies in .pre-commit-config.yaml.

Also fixes several real bugs uncovered by stricter checks: incorrect static
calls to instance methods in swig_backend, wrong return type on get_size,
missing value param in BoardAPI.place_component, variable shadowing in
kicad_process.py, unqualified LibraryManager reference in kicad_interface,
and missing top-level Path import.

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

python/commands/freerouting.py

@@ -95,6 +95,8 @@ def _build_freerouting_cmd(
     """Build the command to run Freerouting."""
     if use_docker:
         docker_exe = _find_docker()
+        if docker_exe is None:
+            raise RuntimeError("Docker/Podman executable not found")
         board_dir = os.path.dirname(dsn_path)
         dsn_name = os.path.basename(dsn_path)
         ses_name = os.path.basename(ses_path)
@@ -120,6 +122,8 @@ def _build_freerouting_cmd(
         ]
     else:
         java_exe = _find_java()
+        if java_exe is None:
+            raise RuntimeError("Java executable not found")
         return [
             java_exe,
             "-jar",
@@ -136,7 +140,7 @@ def _build_freerouting_cmd(
 class FreeroutingCommands:
     """Handles Freerouting autoroute operations."""
 
-    def __init__(self, board=None):
+    def __init__(self, board: Any = None) -> None:
         self.board = board
 
     def _resolve_execution_mode(self, jar_path: str) -> Dict[str, Any]: