[Copilot]

Summary

This pull request hardens side_menu runtime stability and maintainability by fixing lifecycle leaks, removing unnecessary polling, and improving strictness and null-safety across frontend and backend code paths.

Changes

• Frontend lifecycle hardening:
  • Added listener/timer teardown in menu and loader components.
  • Replaced setInterval layout polling in StandardMenu.vue with resize-driven requestAnimationFrame recomputation.
  • Fixed opener/closer accessibility attributes (aria-label) and removed undefined binding usage.
  • Added null/availability guards in helper utilities (menu, dom, setting).
• Store and menu correctness:
  • Removed redundant await await and unused imports in src/store/nav.js.
  • Fixed order index handling where index 0 could be incorrectly dropped.
• Backend strictness and safety:
  • Added declare(strict_types=1); across lib/ PHP files.
  • Replaced loose in_array checks with strict checks.
  • Moved key controllers away from direct \OC::$server session access to injected IUserSession.
  • Added null-user guards in personal/app controller flows.
  • Simplified app ordering comparator logic for predictable sorting.

Impact

• Reduces memory-leak risk from orphaned listeners/timers.
• Cuts unnecessary CPU/layout work from continuous polling.
• Improves resilience against null/undefined runtime states.
• Tightens type and comparison behavior for safer backend execution.

Validation

• PHP syntax lint (php -l) passes for all files under lib/.