feat: Add email settings management and templates functionality

- Implemented email settings configuration in the admin panel, allowing for SMTP settings and notification preferences.
- Created a new template for email settings with fields for SMTP host, port, username, password, sender address, and recipients.
- Added JavaScript functionality to handle loading, saving, and validating email settings.
- Introduced email templates management, enabling the listing, editing, and saving of email templates.
- Updated navigation to include links to email settings and templates.
- Added tests for email settings and templates to ensure proper functionality and validation.

tests/test_admin_email_settings_api.py

@@ -0,0 +1,101 @@
+from __future__ import annotations
+
+import importlib
+
+import pytest
+
+server_app_module = importlib.import_module("server.app")
+app = server_app_module.app
+
+
+@pytest.fixture
+def client():
+    with app.test_client() as client:
+        yield client
+
+
+def login(client):
+    return client.post("/auth/login", data={"username": "admin", "password": "admin"})
+
+
+def test_email_settings_get_requires_auth(client):
+    resp = client.get("/admin/api/email-settings")
+    assert resp.status_code == 302
+    assert resp.headers["Location"] == "/auth/login"
+
+
+def test_email_settings_get_with_auth_returns_defaults(client):
+    login(client)
+
+    resp = client.get("/admin/api/email-settings")
+    assert resp.status_code == 200
+    data = resp.get_json()
+
+    assert data["status"] == "ok"
+    assert isinstance(data["settings"], dict)
+    assert "smtp_host" in data["settings"]
+    assert "schema" in data
+    assert "smtp_host" in data["schema"]
+
+
+def test_email_settings_update_validation_error(client):
+    login(client)
+
+    payload = {
+        "smtp_host": "",
+        "smtp_port": 70000,
+        "smtp_sender": "not-an-email",
+        "smtp_recipients": "owner@example.com, invalid",
+    }
+
+    resp = client.put("/admin/api/email-settings", json=payload)
+    assert resp.status_code == 400
+
+    data = resp.get_json()
+    assert data["status"] == "error"
+    assert "smtp_host" in data["errors"]
+    assert "smtp_port" in data["errors"]
+    assert "smtp_sender" in data["errors"]
+    assert "smtp_recipients" in data["errors"]
+
+
+def test_email_settings_update_persists_and_returns_values(client):
+    login(client)
+
+    payload = {
+        "smtp_host": "smtp.acme.test",
+        "smtp_port": 2525,
+        "smtp_username": "mailer",
+        "smtp_password": "secret",
+        "smtp_sender": "robot@acme.test",
+        "smtp_recipients": "alerts@acme.test, ops@acme.test",
+        "smtp_use_tls": True,
+        "notify_contact_form": True,
+        "notify_newsletter_signups": False,
+    }
+
+    resp = client.put("/admin/api/email-settings", json=payload)
+    assert resp.status_code == 200
+
+    data = resp.get_json()
+    assert data["status"] == "ok"
+    assert data["settings"]["smtp_port"] == 2525
+    assert data["settings"]["smtp_use_tls"] is True
+    assert data["settings"]["smtp_recipients"] == [
+        "alerts@acme.test",
+        "ops@acme.test",
+    ]
+    assert data["settings"]["notify_contact_form"] is True
+    assert data["settings"]["notify_newsletter_signups"] is False
+
+    # Fetch again to verify persistence
+    resp_get = client.get("/admin/api/email-settings")
+    assert resp_get.status_code == 200
+    stored = resp_get.get_json()["settings"]
+    assert stored["smtp_host"] == "smtp.acme.test"
+    assert stored["smtp_port"] == 2525
+    assert stored["smtp_sender"] == "robot@acme.test"
+    assert stored["smtp_recipients"] == [
+        "alerts@acme.test",
+        "ops@acme.test",
+    ]