Implement Job Proposals Functionality

[AhmedFatthy1040]

Issue Title: Implement Job Proposals Functionality

Issue Description:

As a freelancer, I want to submit proposals for job listings posted by clients so that I can express my interest and qualifications for available projects. This functionality should allow freelancers to submit proposals for jobs and enable clients to review those proposals.

Tasks:

1. Submit Proposal:

   • Create an endpoint in the ProposalController for freelancers to submit proposals for specific jobs.
   • Collect necessary details for the proposal, including:
     • job_id: The ID of the job being applied for.
     • freelancer_id: The ID of the freelancer (automatically derived from the authenticated user's context).
     • cover_letter: A cover letter detailing the freelancer's qualifications and interest in the job.
     • proposed_rate: The rate proposed by the freelancer for the job.
     • status: Default to "Pending".

2. Get Proposals for a Job:

   • Create an endpoint to retrieve all proposals submitted for a specific job, accessible by the client who posted the job.

3. Get Proposal Status:

   • Create an endpoint for freelancers to check the status of their proposals for specific jobs.

4. Update Proposal Status:

   • Create an endpoint for clients to update the status of proposals (e.g., Accepted, Rejected).

Acceptance Criteria:

• Submit Proposal:

  • Freelancers should be able to make a POST request to /proposals to submit a proposal.
  • Return 201 Created if the proposal is submitted successfully.
  • Return 400 Bad Request if any required fields are missing or invalid.

• Get Proposals for a Job:

  • Clients should be able to make a GET request to /jobs/{jobId}/proposals to retrieve proposals for their job.
  • Return 200 OK with a list of proposals or 204 No Content if no proposals are found.

• Get Proposal Status:

  • Freelancers should be able to make a GET request to /proposals/{proposalId} to check their proposal status.
  • Return 200 OK with proposal details or 404 Not Found if the proposal does not exist.

• Update Proposal Status:

  • Clients should be able to make a PUT request to /proposals/{proposalId}/status to update the proposal status.
  • Return 200 OK if the update is successful or 404 Not Found if the proposal does not exist.

Endpoint Specifications:

• Submit Proposal:

  • Method: POST
  • URL: /proposals
  • Request Body Example:

    {
      "job_id": 12345,
      "cover_letter": "I am very interested in this job...",
      "proposed_rate": 50.00
    }

• Get Proposals for a Job:

  • Method: GET
  • URL: /jobs/{jobId}/proposals

• Get Proposal Status:

  • Method: GET
  • URL: /proposals/{proposalId}

• Update Proposal Status:

  • Method: PUT
  • URL: /proposals/{proposalId}/status
  • Request Body Example:

    {
      "status": "Accepted"
    }