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_email_settings_service.py

@@ -0,0 +1,167 @@
+from __future__ import annotations
+
+from typing import Any, Dict, List
+
+import pytest
+
+from server.services import email_settings
+
+
+def _defaults() -> Dict[str, Any]:
+    return {
+        field: meta["default"]
+        for field, meta in email_settings.EMAIL_SETTINGS_DEFINITIONS.items()
+    }
+
+
+def test_load_email_settings_returns_defaults_when_storage_empty(monkeypatch):
+    monkeypatch.setattr(email_settings, "get_app_settings", lambda: {})
+
+    settings = email_settings.load_email_settings()
+
+    assert settings == _defaults()
+
+
+def test_load_email_settings_deserializes_persisted_values(monkeypatch):
+    stored = {
+        "email_smtp_host": "smtp.acme.test",
+        "email_smtp_port": "2525",
+        "email_smtp_username": "mailer",
+        "email_smtp_password": "sup3rs3cret",
+        "email_smtp_sender": "robot@acme.test",
+        "email_smtp_use_tls": "false",
+        "email_smtp_recipients": "alerts@acme.test, ops@acme.test",
+        "email_notify_contact_form": "true",
+        "email_notify_newsletter_signups": "false",
+    }
+    monkeypatch.setattr(email_settings, "get_app_settings", lambda: stored)
+
+    settings = email_settings.load_email_settings()
+
+    assert settings["smtp_host"] == "smtp.acme.test"
+    assert settings["smtp_port"] == 2525
+    assert settings["smtp_username"] == "mailer"
+    assert settings["smtp_password"] == "sup3rs3cret"
+    assert settings["smtp_sender"] == "robot@acme.test"
+    assert settings["smtp_use_tls"] is False
+    assert settings["smtp_recipients"] == [
+        "alerts@acme.test",
+        "ops@acme.test",
+    ]
+    assert settings["notify_contact_form"] is True
+    assert settings["notify_newsletter_signups"] is False
+
+
+def test_validate_email_settings_detects_invalid_values():
+    payload = {
+        "smtp_host": "",
+        "smtp_port": "not-a-number",
+        "smtp_sender": "invalid-address",
+        "smtp_recipients": "good@example.com, bad-address",
+        "smtp_use_tls": "maybe",
+    }
+
+    errors = email_settings.validate_email_settings(payload)
+
+    assert "smtp_host" in errors
+    assert "smtp_port" in errors
+    assert "smtp_sender" in errors
+    assert "smtp_recipients" in errors
+    assert "smtp_use_tls" in errors
+
+
+def test_persist_email_settings_serializes_and_updates(monkeypatch):
+    calls: List[tuple[str, str]] = []
+
+    def fake_update(key: str, value: str) -> bool:
+        calls.append((key, value))
+        return True
+
+    monkeypatch.setattr(email_settings, "update_app_setting", fake_update)
+
+    payload = {
+        "smtp_host": "smtp.acme.test",
+        "smtp_port": 2525,
+        "smtp_username": "mailer",
+        "smtp_password": "password123",
+        "smtp_sender": "robot@acme.test",
+        "smtp_use_tls": True,
+        "smtp_recipients": "alerts@acme.test, ops@acme.test",
+        "notify_contact_form": False,
+        "notify_newsletter_signups": True,
+    }
+
+    normalized = email_settings.persist_email_settings(payload)
+
+    assert normalized["smtp_port"] == 2525
+    assert normalized["smtp_use_tls"] is True
+    assert normalized["smtp_recipients"] == [
+        "alerts@acme.test",
+        "ops@acme.test",
+    ]
+    assert normalized["notify_contact_form"] is False
+    assert normalized["notify_newsletter_signups"] is True
+
+    expected_keys = {
+        "email_smtp_host",
+        "email_smtp_port",
+        "email_smtp_username",
+        "email_smtp_password",
+        "email_smtp_sender",
+        "email_smtp_use_tls",
+        "email_smtp_recipients",
+        "email_notify_contact_form",
+        "email_notify_newsletter_signups",
+    }
+    assert {key for key, _ in calls} == expected_keys
+    assert ("email_smtp_port", "2525") in calls
+    assert ("email_smtp_use_tls", "true") in calls
+    assert (
+        "email_smtp_recipients",
+        "alerts@acme.test, ops@acme.test",
+    ) in calls
+
+
+def test_load_effective_smtp_settings_merges_defaults(monkeypatch):
+    monkeypatch.setattr(
+        email_settings,
+        "SMTP_SETTINGS",
+        {
+            "host": "fallback.mail",
+            "port": 465,
+            "username": "fallback",
+            "password": "fallback-pass",
+            "sender": "default@fallback.mail",
+            "use_tls": True,
+            "recipients": ["owner@fallback.mail"],
+        },
+        raising=False,
+    )
+
+    monkeypatch.setattr(
+        email_settings,
+        "load_email_settings",
+        lambda: {
+            "smtp_host": "",
+            "smtp_port": "",
+            "smtp_username": "",
+            "smtp_password": "",
+            "smtp_sender": "",
+            "smtp_use_tls": False,
+            "smtp_recipients": "",
+            "notify_contact_form": True,
+            "notify_newsletter_signups": False,
+        },
+    )
+
+    effective = email_settings.load_effective_smtp_settings()
+
+    assert effective["host"] == "fallback.mail"
+    assert effective["port"] == 465
+    assert effective["username"] == "fallback"
+    assert effective["password"] == "fallback-pass"
+    assert effective["sender"] == "default@fallback.mail"
+    assert effective["use_tls"] is False
+    assert effective["recipients"] == []
+    assert effective["notify_contact_form"] is True
+    assert effective["notify_newsletter_signups"] is False