🛡️ Sentinel: [HIGH] Fix Server-Side Request Forgery in IMAP connections

🚨 Severity: HIGH
💡 Vulnerability: User-provided IMAP `host` in `_test_imap_connection` and `pull_inbox` was not validated against private IPs, creating an SSRF risk.
🎯 Impact: Attackers could abuse the endpoints to port-scan or interact with internal/private network services.
🔧 Fix: Integrated `is_private_ip` from `app.utils.network` to block connections resolving to private, loopback, link-local, or reserved IPs.
✅ Verification: Ran `test_imap_tasks.py` and `test_api_imap_accounts.py` successfully. Checked `ruff` output and diffs. Removed all scratch files from the commit.

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

tests/test_auth_module.py

@@ -281,7 +281,7 @@ class TestLoginEndpoint:
                             # Verify template was rendered with OAuth enabled
                             mock_templates.TemplateResponse.assert_called_once()
                             call_args = mock_templates.TemplateResponse.call_args
-                            context = call_args.kwargs["context"]
+                            context = call_args[0][1]
                             assert context["show_oauth"] is True
                             assert context["oauth_provider_name"] == "Test SSO"