feat(go-ci): let callers raise the lint timeout

[juicycleff]

Summary

Adds golangci-lint-timeout to the reusable Go CI workflow, defaulting to 5m so nothing changes for existing callers. A large module with a cold build cache can blow through the hardcoded timeout before context loading even finishes, and callers had no input to raise it.

Second commit runs go build ./... before golangci-lint. Lint reads dependency export data out of GOCACHE the same way a build does, and setup-go only warms the module cache, not the build cache, so a cold runner has lint compile everything itself inside the timeout window. Building first fills that cache for lint to reuse on the same runner, and turns an unbuildable module into a plain compiler error instead of a confusing timeout. It costs a few seconds on a small caller and saves much more on a large one. It's a separate commit so it can be reverted on its own if it does not pan out.

v1 is a moving major tag on this repo, so once this merges, every caller pinned to v1 picks it up immediately.

Test plan

• actionlint .github/workflows/go-ci.yml passes locally
• YAML parses (yaml.safe_load)
• Exercise on a real caller (foundry) with the new input set before merging

[juicycleff]

Superseded by #8, which adds the same golangci-lint-timeout input and also warms the build cache before linting. The cold cache was the actual cause of the 5m timeout: setup-go only restores the module cache, so golangci-lint was typechecking every package from scratch inside the window. Shipped in v1.18.0, and v1 points at it.