fix: keep init scripts available to page actions

[malsabbagh05]

Summary

• preserve normal context-level init_script registration
• add a marker to detect when the browser backend did not run the init script
• apply the configured init script before page_action only when the marker is missing
• add an async stealth regression test for issue No context persistence for code loaded using init_script #350

Tests

python -m compileall -q scrapling/engines/_browsers tests/fetchers/async/test_stealth_session.py
pytest tests/fetchers/async/test_stealth_session.py tests/fetchers/sync/test_stealth_session.py tests/fetchers/async/test_dynamic_session.py tests/fetchers/sync/test_dynamic.py -q

Result:

19 passed

Also verified the original issue shape against https://example.com, where page_action observed seen [2].

Fixes #350

[samrusani]

Ran a local review/validation pass against commit 84996b7.

Validation:

python -m compileall -q scrapling/engines/_browsers tests/fetchers/async/test_stealth_session.py
python -m pytest tests/fetchers/async/test_stealth_session.py::TestAsyncStealthySession::test_init_script_is_available_in_page_action -q
python -m pytest tests/fetchers/async/test_stealth_session.py tests/fetchers/sync/test_stealth_session.py tests/fetchers/async/test_dynamic_session.py tests/fetchers/sync/test_dynamic.py -q
python -m ruff check scrapling/engines/_browsers/_base.py scrapling/engines/_browsers/_controllers.py scrapling/engines/_browsers/_stealth.py tests/fetchers/async/test_stealth_session.py
git diff --check origin/dev...HEAD

Results: targeted regression passed (1 passed), the listed browser-session suite passed (19 passed), ruff passed, and diff whitespace checks were clean.

I also checked the control flow around page_setup/navigation/page_action; the fallback stays scoped to the configured init_script path and still preserves the normal context-level registration path. I did not find a blocking issue in this patch.

[yetval]

Thanks, but this was already settled in #353: the init script does run, it just sits in a different world than page.evaluate, so isolated_context=False is the whole fix. This patch only re-runs the script after load, which masks the symptom. I'd close in favor of #353.

[samrusani]

Thanks for clarifying. That makes sense: my local pass only validated that this patch made the page_action repro observe the global, not that re-running the script after load was the right fix. I agree the isolated_context=False / docs path in #353 is the cleaner resolution.

[malsabbagh05]

Thanks for the clarification. I agree that the #353 approach is the cleaner fix here, since the issue is the script world/visibility behavior rather than needing to re-run the init script after load. Closing this in favor of #353.