feat(api): remove redundant /env and /api/diagnostic/settings endpoints

- Remove `/api/diagnostic/settings` endpoint (superseded by `/api/settings/`)
- Remove `/env` view route (superseded by `/settings` admin page)
- Delete `env_debug.html` template
- Remove `/env` nav links from base.html (desktop + mobile)
- Update status_dashboard.html to link to /settings instead of /env
- Remove corresponding tests for deleted endpoints
- Update RateLimitingStrategy.md docs

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

tests/test_diagnostic.py

@@ -5,47 +5,6 @@ from unittest.mock import patch
 import pytest
 
 
-@pytest.mark.integration
-class TestDiagnosticSettings:
-    """Tests for diagnostic settings endpoint."""
-
-    def test_diagnostic_settings_endpoint(self, client):
-        """Test /api/diagnostic/settings endpoint."""
-        response = client.get("/api/diagnostic/settings")
-        assert response.status_code == 200
-        data = response.json()
-        assert data["status"] == "success"
-        assert "settings" in data
-        assert "configured_services" in data["settings"]
-
-    def test_diagnostic_settings_has_expected_services(self, client):
-        """Test that diagnostic settings has expected service keys."""
-        response = client.get("/api/diagnostic/settings")
-        data = response.json()
-        services = data["settings"]["configured_services"]
-        expected_keys = ["email", "s3", "dropbox", "onedrive", "nextcloud", "sftp", "openai", "azure"]
-        for key in expected_keys:
-            assert key in services
-
-    def test_diagnostic_settings_includes_workdir(self, client):
-        """Test that settings include workdir."""
-        response = client.get("/api/diagnostic/settings")
-        data = response.json()
-        assert "workdir" in data["settings"]
-
-    def test_diagnostic_settings_includes_hostname(self, client):
-        """Test that settings include external hostname."""
-        response = client.get("/api/diagnostic/settings")
-        data = response.json()
-        assert "external_hostname" in data["settings"]
-
-    def test_diagnostic_settings_includes_imap_status(self, client):
-        """Test that settings include IMAP enabled status."""
-        response = client.get("/api/diagnostic/settings")
-        data = response.json()
-        assert "imap_enabled" in data["settings"]
-
-
 @pytest.mark.integration
 class TestTestNotification:
     """Tests for test notification endpoint."""
@@ -120,66 +79,3 @@ class TestTestNotification:
 
         # Response should have been processed
         assert response.status_code == 200
-
-
-@pytest.mark.unit
-class TestDiagnosticHelpers:
-    """Test helper functions in diagnostic module."""
-
-    @patch("app.utils.config_validator.dump_all_settings")
-    @patch("app.api.diagnostic.settings")
-    def test_dump_all_settings_called(self, mock_settings, mock_dump, client):
-        """Test that dump_all_settings is called."""
-        mock_settings.external_hostname = "test"
-        # Setup minimal mocks for configured services
-        mock_settings.email_host = None
-        mock_settings.s3_bucket_name = None
-        mock_settings.dropbox_refresh_token = None
-        mock_settings.onedrive_refresh_token = None
-        mock_settings.nextcloud_upload_url = None
-        mock_settings.sftp_host = None
-        mock_settings.paperless_host = None
-        mock_settings.google_drive_credentials_json = None
-        mock_settings.uptime_kuma_url = None
-        mock_settings.authentik_config_url = None
-        mock_settings.openai_api_key = None
-        mock_settings.azure_api_key = None
-        mock_settings.azure_endpoint = None
-        mock_settings.imap1_host = None
-        mock_settings.imap2_host = None
-
-        response = client.get("/api/diagnostic/settings")
-
-        # dump_all_settings should have been called
-        mock_dump.assert_called_once()
-
-    @patch("app.api.diagnostic.settings")
-    def test_safe_settings_no_sensitive_data(self, mock_settings, client):
-        """Test that safe settings don't include sensitive data."""
-        mock_settings.workdir = "/tmp/workdir"
-        mock_settings.external_hostname = "test-host"
-        mock_settings.openai_api_key = "sk-secret-key-12345"
-        mock_settings.aws_secret_access_key = "secret-aws-key"
-        # Setup minimal configured services
-        mock_settings.email_host = None
-        mock_settings.s3_bucket_name = None
-        mock_settings.dropbox_refresh_token = None
-        mock_settings.onedrive_refresh_token = None
-        mock_settings.nextcloud_upload_url = None
-        mock_settings.sftp_host = None
-        mock_settings.paperless_host = None
-        mock_settings.google_drive_credentials_json = None
-        mock_settings.uptime_kuma_url = None
-        mock_settings.authentik_config_url = None
-        mock_settings.azure_api_key = None
-        mock_settings.azure_endpoint = None
-        mock_settings.imap1_host = None
-        mock_settings.imap2_host = None
-
-        response = client.get("/api/diagnostic/settings")
-        data = response.json()
-
-        # Sensitive keys should not be in response
-        response_str = str(data)
-        assert "sk-secret-key" not in response_str
-        assert "secret-aws-key" not in response_str