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/pin_locator.py

@@ -9,7 +9,7 @@ import logging
 import math
 import tempfile
 from pathlib import Path
-from typing import Dict, List, Optional, Tuple
+from typing import Any, Dict, List, Optional, Tuple
 
 import sexpdata
 from sexpdata import Symbol
@@ -21,7 +21,7 @@ logger = logging.getLogger("kicad_interface")
 class PinLocator:
     """Locate pins on symbol instances in KiCad schematics"""
 
-    def __init__(self):
+    def __init__(self) -> None:
         """Initialize pin locator with empty cache"""
         self.pin_definition_cache = {}  # Cache: "lib_id:symbol_name" -> pin_data
         self._schematic_cache: Dict[str, object] = {}  # Cache: path -> loaded Schematic
@@ -41,9 +41,9 @@ class PinLocator:
                 "2": {"x": 0, "y": -3.81, "angle": 90, "length": 1.27, "name": "~", "type": "passive"}
             }
         """
-        pins = {}
+        pins: Dict[str, Dict[str, Any]] = {}
 
-        def extract_pins_recursive(sexp):
+        def extract_pins_recursive(sexp: Any) -> None:
             """Recursively search for pin definitions"""
             if not isinstance(sexp, list):
                 return