fix(ci): pyright/mypy extraPaths for adk/src, pytest --import-mode=importlib

Two CI breakages I didn't catch locally:

1. **pyright didn't know about adk/src/** so all `from agentex.lib.*`
   imports failed `reportMissingImports`. Pyright doesn't auto-discover
   editable installs the way Python's runtime does. Fix:
   - Add `extraPaths = ["src", "adk/src"]` at root of [tool.pyright] and
     per execution-environment. This tells pyright to resolve imports
     against both source trees.
   - Update the strict-typecheck execution environment root from the
     deleted `src/agentex/lib` to `adk/src/agentex/lib`.
   - Add a new tests/-equivalent execution environment for `adk/tests`.
   - Same fix for mypy: add `mypy_path = "src:adk/src"`, exclude
     `adk/tests/.*` to match the tests/.* exclusion.

2. **pytest collected tests/ and adk/tests/ as both being top-level
   package `tests`** (both have __init__.py), so it hit "duplicate
   package name" errors:
     ERROR collecting adk/tests/lib/adk - ModuleNotFoundError: No module named 'tests.lib'
   Fix: `--import-mode=importlib` in addopts. This is the modern
   recommended pytest mode and tolerates same-name test packages.

Verified locally with `pytest --collect-only tests adk/tests
--import-mode=importlib`: 2204 tests collected cleanly, no errors.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: max-parke-scale

pyproject.toml

@@ -160,7 +160,10 @@ replacement = '[\1](https://github.com/scaleapi/scale-agentex-python/tree/main/\
 # tests resolve `agentex.lib.*` via the sibling agentex-sdk package installed
 # editably by scripts/bootstrap.
 testpaths = ["tests", "adk/tests"]
-addopts = "--tb=short -n auto"
+# importlib mode avoids the "duplicate package name" collision that classic
+# import mode hits when both tests/ and adk/tests/ have __init__.py making
+# them both look like a top-level `tests` package.
+addopts = "--tb=short -n auto --import-mode=importlib"
 xfail_strict = true
 asyncio_mode = "auto"
 asyncio_default_fixture_loop_scope = "session"
@@ -174,6 +177,12 @@ filterwarnings = [
 typeCheckingMode = "basic"
 pythonVersion = "3.12"
 
+# Both src/ (slim client) and adk/src/ (ADK overlay) contribute to the
+# agentex.* namespace. Pyright needs both as roots so cross-package imports
+# (e.g. agentex.lib.* code referencing agentex.types.*) resolve.
+include = ["src", "adk/src", "tests", "adk/tests", "examples", "scripts", "bin"]
+extraPaths = ["src", "adk/src"]
+
 exclude = [
     "_dev",
     ".venv",
@@ -201,24 +210,34 @@ reportUnknownVariableType = false
 
 # Enable strict type checking only for hand-written code
 [[tool.pyright.executionEnvironments]]
-root = "src/agentex/lib"
+root = "adk/src/agentex/lib"
 typeCheckingMode = "strict"
+extraPaths = ["src", "adk/src"]
 # But allow some flexibility in OpenAI module for complex type boundaries
 reportArgumentType = false
 
 [[tool.pyright.executionEnvironments]]
 root = "examples"
 typeCheckingMode = "strict"
+extraPaths = ["src", "adk/src"]
 # Allow type ignores in tutorials for readability
 reportUnnecessaryTypeIgnoreComment = false
 
 [[tool.pyright.executionEnvironments]]
 root = "tests"
 typeCheckingMode = "basic"
+extraPaths = ["src", "adk/src"]
 # Be loose on typing in tests unless testing types specifically
 reportOptionalMemberAccess = false
 reportArgumentType = false
 
+[[tool.pyright.executionEnvironments]]
+root = "adk/tests"
+typeCheckingMode = "basic"
+extraPaths = ["src", "adk/src"]
+reportOptionalMemberAccess = false
+reportArgumentType = false
+
 [tool.mypy]
 pretty = true
 show_error_codes = true
@@ -229,7 +248,8 @@ show_error_codes = true
 #
 # We also exclude our `tests` as mypy doesn't always infer
 # types correctly and Pyright will still catch any type errors.
-exclude = ['src/agentex/_files.py', '_dev/.*.py', 'tests/.*', 'examples/tutorials/.*']
+exclude = ['src/agentex/_files.py', '_dev/.*.py', 'tests/.*', 'adk/tests/.*', 'examples/tutorials/.*']
+mypy_path = "src:adk/src"
 
 strict_equality = true
 implicit_reexport = true