feat(frontend): implement applied jobs tab

[amankoli09]

Closes #85

Description

This PR implements the applied jobs tab in the artisan listings flow as per issue

Changes

• API Mock Integration: Created a new mock endpoint at src/app/api/applications/route.ts which returns application data with their current states and timestamps.
• AppliedJobsList Component: Created a new AppliedJobsList component that fetches data from /api/applications and dynamically renders the applications. It shows the applied date, job title, company name, application state, and the last updated timestamp.
• State Handling: Integrated loading and empty states inside AppliedJobsList. If a user has no applications, they are shown a friendly empty state message.
• TabPages Integration: Updated TabPages.tsx to mount <AppliedJobsList /> when the "Applied" tab is active.

User Story Addressed

As an artisan, I want to track jobs I applied for, so that I can monitor outcomes.

Acceptance Criteria Met

• Applied tab shows real applications via API integration.
• Empty state shown when no applications exist.
• Shows application state and updated timestamps.