Append keys that exist in the example but are missing from the actual env.
Each appended key uses the example's value as a placeholder (so secrets are
never copied from a real env — the example holds only placeholders).
Existing content is preserved verbatim; new keys are appended under a header.
Append keys that exist in the example but are missing from the actual env. Each appended key uses the example's value as a placeholder (so secrets are never copied from a real env — the example holds only placeholders).
Existing content is preserved verbatim; new keys are appended under a header.