feat: implement user engagement study streaks and dynamic activity heatmap

[Neelr1912]

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

Sustaining student motivation is one of the biggest challenges in e-learning platforms. Currently, users don't have a visual representation of their consistency or daily learning habits. (Resolves #3795)

Describe the solution you'd like

I have integrated user study streak tracking and a dynamic GitHub-style activity heatmap:

1. Activity Log Upgrades: Updated the backend activities schema to accept "login" and "video" activity types, and increased query bounds to support fetching up to 1000 records for yearly calendar views.
2. Auto-Logged Logins: Automatically appends today's date to a new activeDays array in Firestore and records a login activity on the student's first daily visit.
3. Module Completions & Video Watching: Logs completed lessons/modules and lecture videos watched (triggered when a user plays a video for at least 10 cumulative unique seconds), updating the profile's active days.
4. Daily Streak stats card: Displayed a dedicated, flame-themed card showcasing the current daily streak on the profile dashboard.
5. Interactive Timeframe Selector: Enabled dynamically filtering the activity heatmap between a Month, 3 Months, and Year view, with dynamic container widths for clean responsiveness.

Describe alternatives you've considered

A simpler alternative is just a "Total Hours Studied" counter, but a daily streak/heatmap specifically encourages daily platform engagement.

Additional Context

Utilized react-calendar-heatmap styled with Tailwind's utility classes to achieve premium visual quality, interactive hover tooltips, and dynamic intensity colors.

[Neelr1912]

Hi @Premshaw23 now you can merge and close