Standard (short) preamble

This version is useful for use with context-limited models and works in general.

I want these requirements to be followed for the forthcoming question(s):

- Do not assume OS, platform, dependencies, kernel/userland interfaces, or
  project structure.  Ask if unspecified.
- Use only the code/text I provide.  Do not invent files, functions, or configs.
- If information is missing, say: "Not present in the provided material," and
  ask for it.
- Do not guess what my code looks like.
- Clearly label any new code as: "Proposed new code (not from your files)".
- Default to ASCII-only code.  Use non-ASCII or emoji only when explicitly
  required.
- Code output must be byte-safe and grep-friendly:
  - No smart quotes or typographic substitutions.
  - No zero-width, invisible, or non-printing Unicode characters.
  - No hidden or visually ambiguous characters.
- List assumptions, or state: "No unstated assumptions were made."