Add Technical Kiwi website with Go, templ, and HTMX.

Single-page site with gallery by album and event, contact form over SMTP,
Docker dev/prod setup, and on-server image derivatives. Gallery photos stay
local (app/images/ is gitignored).

Co-authored-by: Cursor <cursoragent@cursor.com>

app/internal/contact/validate.go

@@ -0,0 +1,65 @@
+package contact
+
+import (
+	"net/mail"
+	"strings"
+	"unicode/utf8"
+)
+
+const (
+	maxNameLen    = 120
+	maxEmailLen   = 254
+	maxMessageLen = 8000
+	minMessageLen = 10
+)
+
+// Submission is validated contact form input.
+type Submission struct {
+	Name    string
+	Email   string
+	Message string
+}
+
+// Errors maps field names to user-facing messages.
+type Errors map[string]string
+
+func (e Errors) Any() bool {
+	return len(e) > 0
+}
+
+// Parse reads and validates a contact form POST.
+func Parse(name, email, message string) (Submission, Errors) {
+	errs := make(Errors)
+
+	name = strings.TrimSpace(name)
+	email = strings.TrimSpace(email)
+	message = strings.TrimSpace(message)
+
+	if name == "" {
+		errs["name"] = "Name is required."
+	} else if utf8.RuneCountInString(name) > maxNameLen {
+		errs["name"] = "Name is too long."
+	}
+
+	if email == "" {
+		errs["email"] = "Email is required."
+	} else if utf8.RuneCountInString(email) > maxEmailLen {
+		errs["email"] = "Email is too long."
+	} else if _, err := mail.ParseAddress(email); err != nil {
+		errs["email"] = "Enter a valid email address."
+	}
+
+	if message == "" {
+		errs["message"] = "Message is required."
+	} else if utf8.RuneCountInString(message) < minMessageLen {
+		errs["message"] = "Message must be at least 10 characters."
+	} else if utf8.RuneCountInString(message) > maxMessageLen {
+		errs["message"] = "Message is too long."
+	}
+
+	if errs.Any() {
+		return Submission{}, errs
+	}
+
+	return Submission{Name: name, Email: email, Message: message}, nil
+}