ci: drop GOPROXY=direct; GOPRIVATE already routes GrayCodeAI direct

GOPROXY=direct forced the entire module graph (incl. golangci-lint and its
deps) off the public proxy, breaking 'go install golangci-lint'. GOPRIVATE
already fetches GrayCodeAI modules directly from VCS, and the public proxy
has since refreshed tok@v0.1.0 to the moved-tag content, so both paths now
yield the go.sum hash. Reverting the over-broad proxy override.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: Patel230

.github/workflows/ci.yml

@@ -36,11 +36,6 @@ env:
   GOPRIVATE: "github.com/GrayCodeAI/*"
   GONOSUMDB: "github.com/GrayCodeAI/*"
   GONOSUMCHECK: "1"
-  # Fetch GrayCodeAI modules straight from VCS rather than the public module
-  # proxy. The proxy can cache a stale zip for a version whose tag has been
-  # moved (e.g. tok v0.1.0), producing go.sum checksum mismatches; direct git
-  # fetch always matches the current tag content recorded in go.sum.
-  GOPROXY: "direct"
 
 jobs:
   # -------------------------------------------------------------------------