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>

.gitignore

@@ -21,3 +21,19 @@
 # Go workspace file
 go.work
 
+# Air / local build artifacts in app/
+/app/tmp/
+/app/bin/
+
+# Gallery photos and generated derivatives (not in git)
+/app/images/**
+!/app/images/.gitkeep
+
+/bin/
+
+# templ generated (regenerate with `templ generate`)
+/app/templates/*_templ.go
+
+# Local env (copy .env.example)
+.env
+