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/mail/config.go

@@ -0,0 +1,71 @@
+package mail
+
+import (
+	"fmt"
+	"os"
+	"strconv"
+)
+
+// Config holds SMTP relay settings from the environment.
+type Config struct {
+	Host     string
+	Port     int
+	User     string
+	Password string
+	From     string
+	To       string
+	// TLS: "auto" (STARTTLS on 587, plain on 25), "tls" (implicit TLS, e.g. 465), "plain"
+	TLS string
+}
+
+// Load reads SMTP settings from environment variables.
+//
+// Required: SMTP_HOST, SMTP_FROM, SMTP_TO
+// Optional: SMTP_PORT (587), SMTP_USER, SMTP_PASSWORD, SMTP_TLS (auto)
+func Load() (Config, error) {
+	host := os.Getenv("SMTP_HOST")
+	if host == "" {
+		return Config{}, fmt.Errorf("SMTP_HOST is required")
+	}
+
+	from := os.Getenv("SMTP_FROM")
+	if from == "" {
+		return Config{}, fmt.Errorf("SMTP_FROM is required")
+	}
+
+	to := os.Getenv("SMTP_TO")
+	if to == "" {
+		return Config{}, fmt.Errorf("SMTP_TO is required")
+	}
+
+	port := 587
+	if p := os.Getenv("SMTP_PORT"); p != "" {
+		n, err := strconv.Atoi(p)
+		if err != nil {
+			return Config{}, fmt.Errorf("SMTP_PORT: %w", err)
+		}
+		port = n
+	}
+
+	tls := os.Getenv("SMTP_TLS")
+	if tls == "" {
+		tls = "auto"
+	}
+
+	return Config{
+		Host:     host,
+		Port:     port,
+		User:     os.Getenv("SMTP_USER"),
+		Password: os.Getenv("SMTP_PASSWORD"),
+		From:     from,
+		To:       to,
+		TLS:      tls,
+	}, nil
+}
+
+// Enabled reports whether relay settings are present.
+func Enabled() bool {
+	return os.Getenv("SMTP_HOST") != "" &&
+		os.Getenv("SMTP_FROM") != "" &&
+		os.Getenv("SMTP_TO") != ""
+}