the four-part prompt that actually works

Build a function build_prompt(context, goal, constraints, format) that returns a single string with each part on its own line, prefixed by the part name and a colon. Then call it with these four arguments and print the result:

• context: "fastapi route file"
• goal: "add delete handler"
• constraints: "use existing pool"
• format: "diff only"

Expected output:

context: fastapi route file
goal: add delete handler
constraints: use existing pool
format: diff only