Xiaolei Implement Bar Graph named Lessons Learned backend

[niccccccccer]

Description

Related PRS (if any):

None
…

Main changes explained:

• Added a new endpoint for GET /lessons-learnt.

• Implemented filtering by projectId and date range.

• Aggregated lesson counts and calculated the month-over-month percentage change.

How to test:

1. check into current branch

2. do npm install and npm run dev to run this PR locally

3. Get authentication token (normal user)

   Make a POST request to:
   http://localhost:4500/api/login

   Request body (replace with your own credentials):
   {
   "email": "your-email",
   "password": "your-password"
   }

4. Get authentication token (BM Dashboard user)

   Make a POST request to:
   http://localhost:4500/api/bm/login

   Headers:
   Authorization: your-token

   Request body (replace with your own credentials):
   {
   "email": "your-email",
   "password": "your-password"
   }

5. Test GET http://localhost:4500/api/bm/lessons-learnt

   Headers:
   Authorization: your-token (BM Dashboard user)

   Query parameters optional:
   projectId (optional) – Filter by a specific project.
   startDate & endDate (optional) – Retrieve lessons within a date range.

Screenshots or videos of changes:

[akanksha7]

Tested out the endpoint, it is working as expected to return the projectID, project, lessonsCount and changePercentage.

1. Without the query params:

2. With the query params:

[Dharmik1710]

Tested the new /api/bm/lessons-learnt endpoint with and without query parameters. The API returns the expected structure with project, lessonsCount, and changePercentage, supporting filtering by project and date range.

Verified correct behavior across edge cases including empty result sets, invalid project IDs, and partial date filters. All responses return with proper status codes and consistent formatting.

The endpoint integrates cleanly with BM dashboard requirements and works as intended. Good addition for supporting the new visualization.

[pavanputti]

I tested the fix by checking out the current branch, running npm install and npm run dev to start the app locally. I obtained an authentication token for a normal user by sending a POST request to http://localhost:4500/api/login with my credentials. For a BM Dashboard user, I sent a POST request to http://localhost:4500/api/bm/login with the appropriate credentials and token in the Authorization header. I then tested the GET request to http://localhost:4500/api/bm/lessons-learnt using the BM Dashboard user’s token in the Authorization header, optionally including query parameters like projectId, startDate, and endDate, and verified the response was correct.

[one-community]

Thank you all, merging!