[feature] - Repoter login

### Narrative

As a registered reporter
I want to login to my account
so that I can report incidents

### Acceptance Criteria

- **Scenario 1:**
Given a registered reporter
And a registered social account
When they make a login request
Then they should be logged in

- **Scenario 2:**
Given a registered reporter
And an unregistered social account
When they make a login request
Then they should be logged in

- **Scenario 3:**
Given an unregistered reporter
When they make a login request
Login request should be denied

No files or tests are named; start by locating the entry point that handles login requests and review any existing reporter or social-account authentication flow. Check each acceptance scenario against the current behavior, including the expected outcome for an unregistered social account, and confirm the login request is denied for an unregistered reporter.

Written by the indexing model from the issue text.