Copy the shared `.golangci.yml` from the prompts repo unchanged
(sha256 a79b63a254602a5318db5d0e9a06bc71b84bf0c1d896305229d8bfed1d1b1776).
It replaces the deprecated `gomodguard` with `gomodguard_v2`, so lint no
longer prints a deprecation warning, and adds a `depguard` rule that keeps
`net/http/httptest` out of non-test files. No code in this repo breaks
either rule, so nothing else changes.
Model: opus-5-5