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/jlcsearch.py

@@ -7,7 +7,7 @@ jlcsearch service at https://jlcsearch.tscircuit.com/
 
 import logging
 import time
-from typing import Callable, Dict, List, Optional
+from typing import Any, Callable, Dict, List, Optional, Union
 
 import requests
 
@@ -24,12 +24,12 @@ class JLCSearchClient:
 
     BASE_URL = "https://jlcsearch.tscircuit.com"
 
-    def __init__(self):
+    def __init__(self) -> None:
         """Initialize JLCSearch API client"""
         pass
 
     def search_components(
-        self, category: str = "components", limit: int = 100, offset: int = 0, **filters
+        self, category: str = "components", limit: int = 100, offset: int = 0, **filters: Dict
     ) -> List[Dict]:
         """
         Search components in JLCSearch database
@@ -87,7 +87,7 @@ class JLCSearchClient:
             - stock: Available stock
             - price1: Price per unit
         """
-        filters = {}
+        filters: Dict[str, Any] = {}
         if resistance is not None:
             filters["resistance"] = resistance
         if package:
@@ -109,7 +109,7 @@ class JLCSearchClient:
         Returns:
             List of capacitor dicts
         """
-        filters = {}
+        filters: Dict[str, Any] = {}
         if capacitance is not None:
             filters["capacitance"] = capacitance
         if package: