pyproject.toml: Enable mypy.warn_unused_ignores

Add warn_unused_ignores = true to the mypy configuration. This warns
when a '# type: ignore' comment has no associated error code,
ensuring all type ignores are explicit about which error they suppress.

Assisted-by: unsloth/Qwen3.6-35B-A3B-GGUF:IQ4_NL and pi.dev 0.81.1
Signed-off-by: Jan Lindemann <jan@janware.com>

conf/templates/pyproject.toml

@@ -8,6 +8,8 @@
 
   disallow_any_generics = true
 
+  warn_unused_ignores = true
+
   enable_error_code = [
     "explicit-override",
     "ignore-without-code",