Split compose dev/prod and relax contact form friction.

Use compose.dev.yaml and compose.prod.yaml with fixed Go cache mounts, block sudo make dev, build Air outside app/tmp for rootless Docker, soften English spam checks, and simplify contact error copy.

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

app/internal/contact/validate.go

@@ -75,7 +75,7 @@ func Parse(name, email, message string) (Submission, Errors) {
 			case errors.Is(err, contactcheck.ErrName):
 				errs["name"] = "Name is too long."
 			case errors.Is(err, contactcheck.ErrNotEnglish):
-				errs["message"] = "This site only accepts messages written in English. If your message is in English, try adding a few more clear sentences so we can detect the language reliably."
+				errs["message"] = "Please write your message in English."
 			default:
 				errs["message"] = "Could not accept this message."
 			}