… and integration tests

- Fix api_key default from {} to "" in all action handlers
- Delete old manual asyncio test file
- Add test_app_business_reviews_integration.py with pytest.mark.integration, APP_BUSINESS_REVIEWS_API_KEY env var
- Add APP_BUSINESS_REVIEWS_API_KEY to .env.example

…ling ruff config

The previous conftest inserted the tests directory itself onto sys.path,
which is a no-op for the intended purpose of making the integration's
modules importable from test files. Insert the parent (integration root)
instead, matching the pattern from PRs #280, #289, #306, and #307.

With tests/conftest.py putting the integration root on sys.path and
the workspace conftest.py patching Integration.load to find config.json,
test files can now import the integration with a plain
'from app_business_reviews import app_business_reviews'.

Removes the importlib.util.spec_from_file_location dance from both
test files and the now-unused dependencies/ sys.path entry. Also
deletes the legacy tests/context.py shim from the pre-SDK-2.0 testbed.

Matches the simpler pattern used in PRs #280, #289, #306, #307.

…' guards

Both get_reviews_google_play and get_reviews_google_maps tracked the
last response object across the pagination loop just so the post-loop
code could call response.data.get(...) for product/place info, with a
defensive 'if response is not None' guard for the max_pages=0 case.

Capture app_info / place_info inside the loop instead, initialized to
an empty dict before the loop. Same behavior, no defensive guard, no
loop-leaked variable.

…action

Reverts the in-loop assignment introduced in c1455c7. The original code
extracted product_info / place_info from the response variable once
after the pagination loop, which is the more idiomatic shape (one
read, one write).

Keeps the sentinel-and-guard pattern that c1455c7 was meant to clean
up, but adds a comment explaining why the guard is there (max_pages=0
edge case where the loop never executes).