fix(install): #54 safety guards + recovery hint

Offline compose-lock failure now fail-closes (reusing the cache.nixos.org
probe) instead of falling back to a network `nix flake lock`; a disk-review
warn fires when the target already carries Windows/BitLocker/NTFS/LUKS
(before the wipe); account password requires ≥8 chars like LUKS; on HM
pre-activate failure the installer drops a NOMARCHY-DESKTOP-NOT-THEMED.txt
recovery hint in the target home so first login still shows the fix.

Worktree agent; diff reviewed + cherry-picked. V0 flake check + V1
nomarchy-install build. Password ≥8 is V0-complete; the offline/NTFS/
pre-activate scenarios are V2-pending (crafted install runs).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

agent/JOURNAL.md

@@ -17,6 +17,18 @@ Template:
 
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+## 2026-07-09 — #54 installer safety + polish (delegated, worktree)
+- **Task:** NEXT #54. Sonnet worktree agent (installer only).
+- **Did:** offline `compose-lock` failure fail-closes (reuses the
+  cache.nixos.org probe → `OFFLINE`) instead of a network `flake lock`;
+  disk-review `warn` on Windows/BitLocker/NTFS/LUKS signatures (before wipe);
+  account password min 8 (mirrors LUKS); HM pre-activate failure drops a
+  recovery-hint file on the target home. Diff reviewed + cherry-picked.
+- **Verified:** V0 flake check + V1 `nix build .#nomarchy-install`. V2 (offline
+  fail path, NTFS-disk warning, pre-activate hint on a booted target) needs
+  crafted scenarios — queued in slimmed #54. Password ≥8 is V0-complete.
+- **Next:** cheap scripted btop check for #52; then session wrap.
+
 ## 2026-07-09 — #52 theme fidelity Broken/high-ROI fixes (delegated, worktree)
 - **Task:** NEXT #52. Sonnet worktree agent (parallel, theme files only).
 - **Did:** Six defects fixed: rose-pine btop→Dawn, everforest/summer-night