[FEAT] Add tests for src/store/PlannerContext.tsx #124

Is your feature request related to a problem? Please describe.

Our overall test coverage is currently low (~18%). To ensure app stability and prevent regressions, we need to increase test coverage across the codebase. This issue is part of the broader Epic to test Module 1: State & Contexts.

Describe the solution you'd like

Add unit/component tests for src/store/PlannerContext.tsx using Jest and React Native Testing Library.

• Verify the component/hook renders or initializes correctly.
• Test props, state changes, and edge cases.
• Test user interactions if applicable.

Describe alternatives you've considered

N/A

Additional Context

This is a sub-task of #121 [EPIC] Increase Test Coverage.
Check the existing tests in src/utils/__tests__ and src/store/__tests__ for inspiration on how we mock timers and storage.