feat(ui): add register interest modal form to dashboard

[Anjanimhatre]

PR Summary

This PR fixes the issue where the registration form did not provide submission feedback, and form details remained after closing. A new Register Interest button and modal form were added to the dashboard, along with supporting template tags, models, and static configuration.

Issue

• Users were unable to determine if the form was successfully submitted:
• Form details persisted after closing the modal.
• No confirmation message was shown.
• Related Issue: [link-to-issue]

Changes Made

1. UI / Templates

• Added a Register Interest button to the dashboard.
• Added modal form UI in _dashboard.html.
• Updated root.html for proper template inclusion.

2. Backend / Models

• Created Assessment model to fix related errors when accessing the dashboard.
• creaded user interest model
• Added form_extras.py in templatetags to handle custom form logic.

3. Static / Assets

• Configured static directory in local.py for CSS and JS.
• Note: images are still not loading; can fix in a follow-up PR.

4. Environment / Configuration

• Updated .env for proper settings.

5. Behavior / Fixes

• Form now confirms submission with a success message and also provide updation message on resubmission
• Form resets after submission.
• Maintains the same JS logic as before (prevents page reload, closes modal automatically).

6. Documentation / Comments

• Added inline comments in all changed files to indicate the updates and reasoning.

7. How to Test

• Login and navigate to the dashboard.
• Click Register Interest.
• Fill in form details and click Submit.

Verify:

• Form shows a success message.
• Form closes automatically.
• Reopening the form shows it reset.
• Check that no Assessment-related errors occur.

8. Next Steps / Follow-ups

• Fix image loading from static assets.
• Optional: enhance styling or UX for modal form.