feat(api): add contact form endpoint for website enquiries

Add POST /api/v1/contact endpoint to handle contact form submissions
from the marketing website. Includes:
- ContactSchema for validation with HTML sanitization
- Honeypot field for spam protection
- Rate limiting (5 per hour)
- Email notification to info@secuird.tech via NotificationService

gatehouse_app/services/email_templates.py

@@ -496,3 +496,69 @@ def build_email_verification_resend_html(
     {get_alert_box("If you didn't request this, you can safely ignore this email.", "info", "🔒")}
     '''
     return get_base_html(content, "Verify your Secuird email address", "Please verify your email address")
+
+
+def build_contact_enquiry_html(
+    enquiry_type: str,
+    submitter_email: str,
+    name: Optional[str],
+    company: Optional[str],
+    interest_area: Optional[str],
+    message: Optional[str],
+) -> str:
+    """Build a contact enquiry notification email.
+
+    Args:
+        enquiry_type: One of demo_request, sales_enquiry, general, support
+        submitter_email: Email address of the person submitting the enquiry
+        name: Full name of the submitter (optional)
+        company: Company name (optional)
+        interest_area: Area of interest (optional)
+        message: Free-text message (optional)
+
+    Returns:
+        HTML email string
+    """
+    # Map enquiry types to display labels and colors
+    type_labels = {
+        "demo_request": ("Demo Request", "info"),
+        "sales_enquiry": ("Sales Enquiry", "success"),
+        "general": ("General Enquiry", "info"),
+        "support": ("Support Request", "warning"),
+    }
+    type_label, alert_type = type_labels.get(enquiry_type, ("Enquiry", "info"))
+
+    name_display = name if name else "Not provided"
+    company_display = company if company else "Not provided"
+    interest_display = interest_area if interest_area else "Not provided"
+    message_display = message if message else "No message provided"
+
+    # Build details table
+    details_rows = f"""
+    {get_detail_row("Enquiry Type", type_label)}
+    {get_detail_row("Submitter Email", submitter_email)}
+    {get_detail_row("Name", name_display)}
+    {get_detail_row("Company", company_display)}
+    {get_detail_row("Interest Area", interest_display)}
+    """
+
+    content = f'''
+    <h2 style="margin: 0 0 20px 0; color: {TEXT_COLOR}; font-size: 20px; font-weight: 600;">New {type_label}</h2>
+    <p style="margin: 0 0 20px 0; color: {TEXT_COLOR}; font-size: 15px; line-height: 1.6;">
+        A new {type_label.lower()} has been submitted through the Secuird website.
+    </p>
+    {get_alert_box(f"Enquiry type: <strong>{type_label}</strong>", alert_type, "📬")}
+    <table role="presentation" width="100%" cellspacing="0" cellpadding="0" style="margin: 20px 0; background-color: {BACKGROUND_COLOR}; border-radius: 8px;">
+        <tr>
+            <td style="padding: 20px;">
+                <h3 style="margin: 0 0 16px 0; color: {TEXT_COLOR}; font-size: 14px; font-weight: 600;">Enquiry Details</h3>
+                <table role="presentation" width="100%" cellspacing="0" cellpadding="0">
+                    {details_rows}
+                </table>
+            </td>
+        </tr>
+    </table>
+    <h3 style="margin: 20px 0 12px 0; color: {TEXT_COLOR}; font-size: 14px; font-weight: 600;">Message</h3>
+    <p style="margin: 0; color: {TEXT_COLOR}; font-size: 14px; line-height: 1.6; white-space: pre-wrap;">{message_display}</p>
+    '''
+    return get_base_html(content, f"Secuird Website: {type_label}", f"New {type_label} from {submitter_email}")