Add registration validation and more activities

[vaariable]

This pull request enhances the activity management system by adding new activities, improving signup validation, and enhancing the frontend to display participant details. Key changes include expanding the in-memory database, adding validation to prevent duplicate signups, and updating the UI to show participant lists with styled formatting.

Backend Enhancements:

• Added six new activities (Soccer Team, Basketball Team, Art Club, Drama Club, Math Club, and Science Club) to the in-memory activities database, each with descriptions, schedules, maximum participants, and initial participant lists. (src/app.py, src/app.pyR24-R59)
• Updated the signup_for_activity function to include a validation step that prevents students from signing up for the same activity multiple times. If a duplicate signup is detected, an HTTP 400 error is raised. (src/app.py, src/app.pyR101-R104)

Frontend Improvements:

• Enhanced the activity card UI to display a list of participants for each activity. If no participants are signed up, a placeholder message ("No participants yet.") is shown. (src/static/app.js, src/static/app.jsR23-R35)
• Introduced new CSS styles for the participants section, including a bordered and highlighted box with styled headers and list items for better readability. (src/static/styles.css, src/static/styles.cssR139-R161)

[Copilot]

Pull Request Overview

This pull request enhances the activity management system by adding several new activities, preventing duplicate signups, and improving the UI to display participant details.

• Expanded the in-memory activities database with six new clubs
• Added duplicate-signup validation in the backend
• Updated the activities card UI to dynamically display the list of participants

Reviewed Changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/app.py	Added new activities and duplicate signup validation
src/static/app.js	Enhanced UI to display participants with a conditional placeholder

Files not reviewed (1)

• src/static/styles.css: Language not supported

Comments suppressed due to low confidence (1)

src/static/app.js:24

• Directly injecting participant data into the innerHTML could expose a potential XSS risk if the data is ever manipulated in an unexpected way. Consider sanitizing the participant values or using safer methods to populate list items.

const participantsList = details.participants.length ? `<ul>${details.participants.map(participant => `<li>${participant}</li>`).join('')}</ul>` : "<p>No participants yet.</p>";

[Copilot]

[nitpick] Consider adding a comment block to summarize the new activities in the in-memory database for improved readability and maintenance.

Suggested change

	# In-memory activity database
	# In-memory activity database
	# This dictionary stores information about extracurricular activities available at Mergington High School.
	# Each activity is represented as a key-value pair, where the key is the activity name (string) and the value
	# is a dictionary containing:
	# - "description": A brief description of the activity.
	# - "schedule": The days and times the activity takes place.
	# - "max_participants": The maximum number of participants allowed.
	# - "participants": A list of email addresses of current participants.