fix: debounce modal open and guard duplicate analyze triggers

[ananyashree2633]

Description

Fix rapid double-click on Analyze button causing duplicate API calls and inconsistent state/crash.

Related Issue

Fixes #539

Type of change

• [✅ ] Bug fix
• New feature / enhancement
• Documentation update
• [ ✅] Test addition
• Refactor

Checklist

• [ ✅] I have read CONTRIBUTING.md
• [ ✅] My branch is up to date with main
• [✅ ] I have run pytest -v and all tests pass
• [✅ ] I have not introduced duplicate issues or features
• [✅ ] My PR title follows the format: feat/fix/docs/test: short description
• [✅ ] I have added tests for new features (Level 2 and 3 issues)
• [✅ ] No hardcoded secrets or API keys in my code
• [✅ ] This PR is linked to a GSSoC 2026 issue

Screenshots (if frontend

Screen Recording 2026-06-22 at 1.24.40 AM.mov.zip

Test evidence

PASSED tests/test_endpoints.py::test_analyze_concurrent_calls_idempotent
===================================== 56 passed, 1 warning in 0.29s =====================================

[imDarshanGK]

@ananyashree2633
Please add a video demo of the feature

[ananyashree2633]

Hi @imDarshanGK,

Locally all black and isort checks pass:

• git diff --name-only origin/main...HEAD -- '*.py' | xargs black --check ✅ 22 files unchanged
• git diff --name-only origin/main...HEAD -- '*.py' | xargs isort --check-only ✅

The failing CI run shows "failed 1 hour ago in 7s" which appears to be a cached old run. Could you please re-run the CI checks? Thank you!

[ananyashree2633]

All changes implemented and tested:

• Added isAnalyzing guard flag
• Added debounce on analyze button
• Added regression test
• All 56 tests passing
• Video demo added