refactor: enforce BasedPyright strict type checking (#5158)

pyproject.toml

@@ -94,6 +94,7 @@ dev = [
     "pytest-cov>=6.0.0,<7.0.0",
     "pytest-xdist>=3.8.0,<4.0.0",
     "ruff>=0.1.0",
+    "basedpyright>=1.39.0,<2.0.0",
     "pymupdf>=1.25.0",
     "pypdf>=5.0.0,<6.0.0",
     "python-docx>=1.1.0,<2.0.0",
@@ -164,6 +165,12 @@ target-version = "py311"
 select = ["E", "F", "I", "N", "W"]
 ignore = ["E501"]
 
+[tool.basedpyright]
+include = ["nanobot"]
+exclude = ["**/tests"]
+typeCheckingMode = "strict"
+pythonVersion = "3.11"
+
 [tool.pytest.ini_options]
 asyncio_mode = "auto"
 testpaths = ["tests", "nanobot/channels"]