Non-interactive terraform prod apply: use a saved plan file, not `yes |`

Apply terraform to production from a non-interactive context (an agent, a script, CI) when the repo's `apply.sh` / `deploy.sh` wrapper calls `terraform apply` WITHOUT `-auto-approve` and therefore blocks on the "Enter a value:" prompt. Use when: (1) a wrapper script hangs or dies at the approval prompt, (2) you are about to reach for `echo yes | ./apply.sh`, (3) you reviewed a plan and want the apply to be that plan rather than a freshly recomputed one, (4) a wrapper auto-detects variables (image tag, version) from `terraform output` and you need to reproduce them, (5) you want an apply that fails loudly if state moved under you. Covers the approve-the-wrong-plan race tha…