Resolve outstanding `mage check:go` linter findings

[ebeahan]

Summary

Resolve the outstanding golangci-lint findings reported by mage check:go on main.

Current findings:

407 issues:
* errcheck: 18
* gocheckcompilerdirectives: 1
* goconst: 351
* gosec: 12
* misspell: 1
* noctx: 5
* nolintlint: 4
* prealloc: 5
* staticcheck: 10

Criteria for completion

• All current reported findings are addressed.
• mage check:go exits 0 on main (no findings, no panics).
• No new //nolint: annotations introduced unless accompanied by an explanatory comment per the nolintlint rule.