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>

pyproject.toml

@@ -23,15 +23,20 @@ disable_error_code = [
     "arg-type",
     "attr-defined",
     "union-attr",
-    "call-arg",
-    "assignment",
     "var-annotated",
-    "annotation-unchecked",
     "index",
-    "has-type",
-    "dict-item",
-    "misc",
-    "list-item",
-    "return-value",
-    "operator",
 ]
+
+[[tool.mypy.overrides]]
+module = [
+    "pcbnew",
+    "cairosvg",
+    "sexpdata",
+    "skip",
+    "kipy",
+    "kipy.*",
+    "schematic",
+    "PIL",
+    "PIL.*",
+]
+ignore_missing_imports = true