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/schematic.py

@@ -2,6 +2,7 @@ import logging
 import os
 import shutil
 import uuid
+from typing import Any, Optional
 
 from skip import Schematic
 
@@ -12,7 +13,7 @@ class SchematicManager:
     """Core schematic operations using kicad-skip"""
 
     @staticmethod
-    def create_schematic(name, metadata=None):
+    def create_schematic(name: str, metadata: Optional[Any] = None) -> Any:
         """Create a new empty schematic from template"""
         try:
             # Determine template path (use template_with_symbols for component cloning support)
@@ -70,7 +71,7 @@ class SchematicManager:
             raise
 
     @staticmethod
-    def load_schematic(file_path):
+    def load_schematic(file_path: str) -> Optional[Any]:
         """Load an existing schematic"""
         if not os.path.exists(file_path):
             logger.error(f"Schematic file not found at {file_path}")
@@ -84,7 +85,7 @@ class SchematicManager:
             return None
 
     @staticmethod
-    def save_schematic(schematic, file_path):
+    def save_schematic(schematic: Any, file_path: str) -> bool:
         """Save a schematic to file"""
         try:
             # kicad-skip uses write method, not save
@@ -96,7 +97,7 @@ class SchematicManager:
             return False
 
     @staticmethod
-    def get_schematic_metadata(schematic):
+    def get_schematic_metadata(schematic: Any) -> dict[str, Any]:
         """Extract metadata from schematic"""
         # kicad-skip doesn't expose a direct metadata object on Schematic.
         # We can return basic info like version and generator.