feat(menu): #76 slice 2 — Hibernate notifies on failure

Per the settled #76 UX call: keep the Power-menu Hibernate row
unconditional, but when hibernate fails (typically a swap=0 machine with
no disk swap), surface a notification pointing at the enable-hibernation
runbook instead of a silent no-op. On success `systemctl hibernate`
blocks until resume, so the notify only fires on a real failure.

Verification: V1 — homeConfigurations.nomarchy.activationPackage builds
(rebuilds nomarchy-menu; writeShellScriptBin runs bash -n). Control-flow
proved on the arm extracted from the built script: failing systemctl ->
notify fires, succeeding -> no notify. flake check --no-build green.
V2 hibernate->resume VM test + V3 laptop remain open (#76 slice 3).

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

agent/JOURNAL.md

@@ -17,6 +17,25 @@ Template:
 
 ---
 
+## 2026-07-10 — #76 slice 2: Hibernate notify-on-failure
+- **Task:** BACKLOG #76 remaining slice 2 — per the settled "keep row, notify
+  on failure" call.
+- **Did:** `modules/home/rofi.nix` power menu Hibernate arm now runs
+  `systemctl hibernate 2>/dev/null || notify-send "Hibernate" "…see
+  docs/MIGRATION.md"`. On success the call blocks until resume, so the notify
+  only fires on a genuine failure (e.g. swap=0 no-swap machine). Row stays
+  unconditional (no hiding).
+- **Verified:** **V1** — `nix build …homeConfigurations.nomarchy.activationPackage`
+  green (rebuilds `nomarchy-menu.drv`; `writeShellScriptBin` runs bash -n at
+  build). Control-flow proof on the arm extracted from the built script:
+  failing `systemctl` → notify fires; succeeding → no notify. `nix flake
+  check --no-build` green.
+- **Pending:** slice 3 = the V2 hibernate→resume VM test + V3 laptop
+  (Hibernate→power off→resume on the LUKS+@swap machine; plus confirm the
+  no-swap notify surfaces in a real session). Both remain open on #76.
+- **Next suggestion:** slice 3 — add a `checks.*` hibernate VM test (as far
+  as QEMU allows) and queue the V3 laptop steps in HARDWARE-QUEUE.
+
 ## 2026-07-10 — #76 slice 1: MIGRATION.md hibernation runbook
 - **Task:** BACKLOG #76 remaining slice 1 — docs runbook for enabling
   hibernation on an existing machine (per the settled "docs not tool" call).