[Projects] Add Get Project Members Route (GET /projects/{id}/members)

[nourshoreibah]

User Story

As a user I want to view all project members and their roles so that I can understand who has access.

Description

• Add GET route to projects Lambda.
  Command:
  node tools/lambda-cli.js add-route projects GET /projects/{id}/members
• Join proj_member with project_memberships using projectID.
• Return member and role fields.

Acceptance Criteria

• Returns 200 with members array.
• Returns empty array if no members.