Fix pre-existing gosec G118 findings on main (blocks lint CI)

[kaidaguerre]

golangci-lint reports 3 gosec G118 findings on main (G118 is enabled and not excluded in .golangci.yml), so the main lint job fails independently of any feature work:

• internal/cmdconfig/cmd_hooks.go:101
• internal/dashboardserver/api.go:23
• internal/db_client/db_client_execute.go:159

These pre-date and are unrelated to the pgx v5.9.2 / CVE-2026-41889 bump (verified: identical on unmodified origin/main; the pgx PR diff adds 0 new lint issues). They block the main lint job for #1060's main backport PR #1062 from going green.

Scope: fix exactly these 3 findings (narrowest fix), no unrelated cleanup. v1.5.x is lint-clean and not affected.

[github-actions]

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