feat(frontend): add confirmation modal before deleting a chat session (#362)

[annukumar123]

Description

Closes #362.

• The Problem: Clicking the delete cross icon (×) next to a chat session instantly triggered onDeleteSession(s.id), wiping out the user's history from the local SQLite database without warning. This is prone to accidental clicks, especially on mobile devices.
• The Fix: Added stateful validation to intercepts delete clicks:
  • Tracks the target session using sessionToDelete component state.
  • Displays a clean, modal dialog with warning instructions.
  • Executes deletions only upon user confirmation.
  • Styled using the project's existing Tailwind CSS borders, background shadows, and color scheme.

Hackathon Association

• Program: Social Summer of Code (SSoC) 2026
• Contributor Role: Student Participant
• Leaderboard Tracking: Please label this PR with the appropriate SSoC difficulty tags (e.g., ssoc, level-1) so it registers for leaderboard points.

[vercel]

@annukumar123 is attempting to deploy a commit to the Darshan's projects Team on Vercel.

A member of the Team first needs to authorize it.

[adikulkarni006]

@annukumar123 Good work! The confirmation modal looks clean and follows the shadcn pattern. However, a few things need to be fixed before merging:

1. Branch out-of-date – Please merge the latest main into your branch and resolve any conflicts.
2. Missing SSoC labels – Request maintainer @imDarshanGK to add SSoC26 and good-first-issue (or Easy) labels.
3. CI pending – Once the branch is updated and maintainer approves the workflow, CI will run.

Please update your branch (git merge main) and push. Then we can review again.

@imDarshanGK Could you please approve the workflow and add the necessary labels when ready? Thanks.

[adikulkarni006]

git checkout feature/chat-delete-confirmation-modal
git fetch origin
git merge origin/main

fix conflicts if any

git push origin feature/chat-delete-confirmation-modal

[annukumar123]

@adikulkarni006 Thanks for the review! I have successfully merged the latest main branch into this feature branch and pushed the changes. The PR should be up-to-date now and ready for the CI checks to run. Let me know if everything looks good on your end! 😊