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/gallery/hero_test.go

@@ -0,0 +1,22 @@
+package gallery
+
+import "testing"
+
+func TestSelectHero_configured(t *testing.T) {
+	t.Setenv("HERO_IMAGE", "connectionmachine/20220723_231556.jpg")
+	images := []Image{
+		{RelPath: "templeoftechno/IMG_20250817_020719.jpg"},
+		{RelPath: "connectionmachine/20220723_231556.jpg", HeroURL: "/images/hero/connectionmachine/20220723_231556.jpg"},
+	}
+	hero, ok := SelectHero(images)
+	if !ok || hero.RelPath != "connectionmachine/20220723_231556.jpg" {
+		t.Fatalf("got %+v ok=%v", hero, ok)
+	}
+}
+
+func TestParseDate_20220723(t *testing.T) {
+	tm, year := parseDate("20220723_231556.jpg")
+	if tm.IsZero() || year != 2022 {
+		t.Fatalf("got %v year=%d", tm, year)
+	}
+}