Replace `.golangci.yml` with the canonical file from `sneak/prompts`,
byte for byte. It runs `gomodguard_v2` in place of the deprecated
`gomodguard`, which removes the deprecation warning from every lint run,
and enables a `depguard` rule keeping `net/http/httptest` out of non-test
files. Neither raised a finding in this repo.
Model: opus-5-5
sneak