Phase-1c: true verification = Adversary deletes the throwaway VM, creates a fresh one, full install

Strengthen C4/W5: the genuine reproducibility proof is a clean-room repeat — the Adversary
destroys any existing throwaway VM, creates a brand-new blank VM, and runs the entire install
from scratch per docs/install.md so nothing from the Builder's setup attempt can mask a gap.
Cold, with logged evidence (VM id, exact install commands, convergence + TLS-from-git-cert).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

cc-ci-plan/plan-phase1c-full-reproducibility.md

@@ -90,10 +90,16 @@ Terminates only when every item holds **and the Adversary has independently re-v
       webhook HMAC, registry creds, host age recipients) is sops-encrypted in git. The **only**
       out-of-band secret is the bootstrap age key — documented precisely, nothing else.
 - [ ] **C4 — Genuine throwaway-VM live rebuild.** On a blank NixOS VM (Incus, `terraform-ci`),
-      provisioned with *only* the bootstrap age key, the loops `git clone` base+instance and run
+      provisioned with *only* the bootstrap age key, the loops `git clone` base+secrets and run
       `nixos-rebuild switch`; the system activates and the reconcile oneshots converge
       (swarm/proxy/drone/bridge/dashboard), all secrets incl. the cert decrypt, with **no manual step
-      not in `docs/install.md`**. The Adversary performs this **cold** and logs evidence.
+      not in `docs/install.md`**.
+      **The true proof is a clean-room repeat (C4 done right):** the Adversary **deletes** any
+      existing throwaway VM, **creates a brand-new blank VM via Incus**, and runs the *entire* install
+      from scratch (clone base+secrets → provision age key → `nixos-rebuild switch` → everything comes
+      up) — proving reproducibility on a genuinely fresh machine, with **no residue** from the
+      Builder's setup attempt masking a gap. Done **cold** by the Adversary, with logged evidence
+      (VM id, the exact commands from `docs/install.md`, convergence + TLS-from-git-cert proof).
 - [ ] **C5 — Honest D8.** The D8 evidence is rewritten: byte-identical closure (static) **plus** the
       live throwaway-VM rebuild (dynamic). The "infeasible by design" wording is removed. If any
       single aspect genuinely can't be reproduced, it is a narrowly-scoped, Adversary-signed-off
@@ -144,9 +150,12 @@ out — see memory).
 4. **W4 — Reproducible live rebuild.** On the throwaway VM: clone base+instance, `nixos-rebuild
    switch`, watch oneshots converge, secrets+cert decrypt. *Accept:* system fully up with **no step
    outside `docs/install.md`**; capture evidence.
-5. **W5 — Adversary cold proof + honest D8.** Adversary repeats W4 from scratch independently and
-   rewrites the D8 evidence (static + live), removing "infeasible by design." *Accept:* Adversary
-   logs a real D8 live-rebuild PASS (or a narrow, signed-off limitation per §3 C5).
+5. **W5 — Adversary clean-room proof + honest D8.** The Adversary **deletes** the Builder's throwaway
+   VM, **creates a brand-new blank VM**, and runs the full install from scratch per `docs/install.md`
+   (clone base+secrets → provision age key → `nixos-rebuild switch` → all up) — a genuinely fresh
+   machine, no residue. Then rewrites the D8 evidence (static byte-identical + this live clean-room
+   rebuild), removing "infeasible by design." *Accept:* Adversary logs a real D8 live-rebuild PASS on
+   a freshly-created VM (or a narrow, signed-off limitation per §3 C5).
 6. **W6 — Cleanup + docs + final sizing.** Destroy the throwaway VM; update all docs (C7); decide and
    apply final `cc-nix-test` sizing. *Accept:* no leftover VM/secret leak; docs match; flip Phase-1c
    `STATUS.md` to `## DONE`.