Fix "invalid user_code" error when revoking device auth

[KCarretto]

Fixes a bug where revoking a device authorization via the UI results in an "invalid user_code" error.

Changes:

• Updated tavern/internal/www/src/pages/profile/DeviceAuth.tsx to pass node.userCode instead of node.id to the handleRevokeDevice function.
• Created tavern/internal/http/device_auth_test.go and added a test suite for NewRDARevokeHandler to ensure the revoke API endpoint functions correctly and handles both admin and normal user authorization constraints.

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PR created automatically by Jules for task 10053009158567028608 started by @KCarretto

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[github-actions]

Summary

Tests 📝	Passed ✅	Failed ❌	Skipped ⏭️	Other ❓	Flaky 🍂	Duration ⏱️
2752    ±0	2752    ±0	0    ±0	0    ±0	0    ±0	0    ±0	1ms    ±0

Previous Results

Build 🏗️	Result 🧪	Tests 📝	Passed ✅	Failed ❌	Skipped ⏭️	Other ❓	Flaky 🍂	Duration ⏱️
#1533	✅	2752	2752	0	0	0	0	38.9s

Insights

Average Tests per Run	Total Flaky Tests	Total Failed	Slowest Test (p95)
2752	0	0	5.5s

Slowest Tests

Test 📝	Results 📊	Duration (avg) ⏱️	Duration (p95) ⏱️
TestDockerExecutor_Build_ContextCancellation	1	5.5s	5.5s
eldritch-libsys: std::dll_inject_impl::tests::test_dll_inject_simple	1	5.2s	5.2s
TestInteractiveShell	1	5.1s	5.1s
TestOtherStreamOutput	1	5.0s	5.0s
imix::bin/imix: install::tests::test_install_execution	3	1.6s	4.7s
imix::bin/imix: install::tests::test_install_execution	3	1.6s	4.7s
imix::bin/imix: install::tests::test_install_execution	3	1.6s	4.7s
imix::bin/imix: tests::task_tests::test_task_streaming_output	3	3.0s	3.0s
imix::bin/imix: tests::task_tests::test_task_streaming_output	3	3.0s	3.0s
imix::bin/imix: tests::task_tests::test_task_streaming_output	3	3.0s	3.0s

_{🎉 No failed tests in this run. | 🍂 No flaky tests in this run.}

Github Test Reporter by CTRF 💚