chore(ci): add govulncheck, staticcheck, go vet, gofumpt gates

* Add lint/format checks to the Gitea release workflow and Makefile
  (targets: vet, fmt, fmt-check, staticcheck, govulncheck, check)
* Switch .golangci.json formatter from gofmt to gofumpt (extra.group-params)
* Bump golang.org/x/text 0.37.0 -> 0.39.0 for GO-2026-5970; re-vendor
* Fix staticcheck S1011 in pkg/diff; drop unused pgsql writer helpers
* Fix gocritic unnamedResult (pkg/diff) and rangeValCopy (pkg/pgsql)
* Apply gofumpt + goimports formatting across the tree

vendor/golang.org/x/sys/cpu/cpu_riscv64.go

@@ -16,6 +16,7 @@ func initOptions() {
 		{Name: "zba", Feature: &RISCV64.HasZba},
 		{Name: "zbb", Feature: &RISCV64.HasZbb},
 		{Name: "zbs", Feature: &RISCV64.HasZbs},
+		{Name: "zbc", Feature: &RISCV64.HasZbc},
 		// RISC-V Cryptography Extensions
 		{Name: "zvbb", Feature: &RISCV64.HasZvbb},
 		{Name: "zvbc", Feature: &RISCV64.HasZvbc},