Add tracking for Preserve Intent banner actions (#9409)

[Sadashii]

Closes #9409

Adds link tracking tags (data-ol-link-track) to the "continue" and "dismiss" options on the Preserve Intent login-redirect banner, and ensures the pending_action cookie is cleared upon successful login with a valid redirect target.

Technical

• Dynamically applies data-ol-link-track="PreserveIntent|Continue" and data-ol-link-track="PreserveIntent|Dismiss" to the respective banner elements using JavaScript at DOMContentLoaded in view.html.
• Clears the pending_action cookie in the legacy login handler (openlibrary/plugins/upstream/account.py) and the FastAPI login handler (openlibrary/fastapi/account.py) when the redirect is safe and not blacklisted.
• Added comprehensive unit tests for both legacy and FastAPI login redirect/cookie clearing behaviors.

Testing

Run Python tests:

pytest openlibrary/plugins/upstream/tests/test_account.py openlibrary/tests/fastapi/test_account.py

Manually verified behaviour, cookie is deleted with correct redirect and the html attributes are present on web view.

Screenshot

N/A

Stakeholders

@mekarpeles

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adds client-side link tracking metadata for “pending action” banner interactions on the account view page.

Changes:

• Add data-ol-link-track to the “Continue” link.
• Add data-ol-link-track to the dismiss/close control for the banner.

[mekarpeles]

Thanks for the PR, @Sadashii!

Copilot has been assigned for an initial review.

@mekarpeles is assigned to this PR and currently has:

• 0 open PR(s) of equal or higher priority to review first

Possible improvements for this PR

• Proof of testing — the testing section covers style checks but doesn't describe how the tracking attributes were verified at runtime (e.g., confirming that data-ol-link-track values appear on the expected DOM elements, or that analytics events fire when the banner buttons are clicked). A brief note on what was manually checked would help reviewers.

PR triage checklist (maintainers / Pam)

• PR description — not empty; explains what the change does and how to verify it
• References an issue — PR body contains a #NNN reference
  • Linked issue is triaged — has a Priority: * label (not just Needs: Triage)
  • Linked issue is assigned — has at least one assignee
• Commit history clean — no WIP/fixup/conflict noise; commit messages are meaningful
• CI passing — no failing check-runs
• Test cases present — if the change touches substantive logic, test coverage exists or is explained
• Proof of testing — PR body includes a description of what was tested, a screenshot, or a video

Note

This comment was automatically generated by Pam, Open Library's Project AI Manager, on behalf of @mekarpeles. Pam is designed to provide status visibility, perform basic project management functions and relevant codebase research, and provide actionable feedback so contributors aren't left waiting.