fix: add polling to make OAuth flows more robust to popup communication failure

[connorlindsey]

Description

In some cases, window.postMessage fails, so this PR adds some polling to see if the connection has been established.

Checklist

• Tests have been added for new features or major refactors to existing features.

Screenshots or videos

Example where I hard-coded the popup HTML response to not auto close or send the success message. The button updating to 'Connected' and closing the popup is from the polling codepath.
https://github.com/user-attachments/assets/bc411148-643d-4e8a-9175-d567ac37a25c

[linear]

KNO-11283 [Switchboard] Multiple reports of Slack OAuth connection issue

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Review	Updated (UTC)
javascript-ms-teams-connect-example	Ready	Preview, Comment	Jan 22, 2026 5:43pm
javascript-nextjs-example	Ready	Preview, Comment	Jan 22, 2026 5:43pm
javascript-slack-connect-example	Ready	Preview, Comment	Jan 22, 2026 5:43pm
javascript-slack-kit-example	Ready	Preview, Comment	Jan 22, 2026 5:43pm

[changeset-bot]

🦋 Changeset detected

Latest commit: 6dce500

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 11 packages

Name	Type
@knocklabs/react-core	Patch
@knocklabs/react	Patch
@knocklabs/expo	Patch
@knocklabs/react-native	Patch
guide-example	Patch
ms-teams-connect-example	Patch
nextjs-app-dir-example	Patch
nextjs-example	Patch
slack-connect-example	Patch
slack-kit-example	Patch
@knocklabs/expo-example	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[mattmikolay]

🍩

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

^{Bugbot Autofix is OFF. To automatically fix reported issues with Cloud Agents, enable Autofix in the Cursor dashboard.}

[codecov]

Codecov Report

❌ Patch coverage is 88.00000% with 21 lines in your changes missing coverage. Please review.
✅ Project coverage is 68.45%. Comparing base (f6e494a) to head (6dce500).
⚠️ Report is 1 commits behind head on main.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
...components/MsTeamsAuthButton/MsTeamsAuthButton.tsx	74.19%	8 Missing ⚠️
...ack/components/SlackAuthButton/SlackAuthButton.tsx	74.19%	8 Missing ⚠️
...eact-core/src/modules/core/hooks/useAuthPolling.ts	95.23%	3 Missing ⚠️
...e/src/modules/slack/context/KnockSlackProvider.tsx	50.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #830      +/-   ##
==========================================
+ Coverage   67.84%   68.45%   +0.60%     
==========================================
  Files         190      193       +3     
  Lines        7934     8052     +118     
  Branches     1041     1062      +21     
==========================================
+ Hits         5383     5512     +129     
+ Misses       2526     2515      -11     
  Partials       25       25              

Files with missing lines	Coverage Δ
packages/react-core/src/index.ts	100.00% <ø> (ø)
...ackages/react-core/src/modules/core/hooks/index.ts	100.00% <100.00%> (ø)
...c/modules/core/hooks/useAuthPostMessageListener.ts	100.00% <100.00%> (ø)
packages/react-core/src/modules/core/index.ts	100.00% <100.00%> (ø)
packages/react-core/src/modules/core/types.ts	100.00% <100.00%> (ø)
.../modules/ms-teams/context/KnockMsTeamsProvider.tsx	92.00% <100.00%> (+0.51%)	⬆️
...dules/ms-teams/hooks/useMsTeamsConnectionStatus.ts	87.75% <ø> (ø)
...rc/modules/slack/hooks/useSlackConnectionStatus.ts	90.00% <ø> (ø)
packages/react/src/modules/core/utils.ts	71.42% <100.00%> (ø)
...e/src/modules/slack/context/KnockSlackProvider.tsx	18.18% <50.00%> (+0.87%)	⬆️
... and 3 more