feat(doctor): #77 hibernate/sleep section (VISION § C)

nomarchy-doctor gains a read-only hibernate/sleep section (the highest-ROI
Day-2 gap, a natural #76 follow-on): resume device on the kernel cmdline
(+ resume_offset for a swapfile), disk swap >= RAM, zram active, and any
suspend/hibernate error in the previous boot's kernel log. Self-gates
(skip on swap=0) and emits only ok/warn/skip, so it never fails the sheet.
Adds `hibernate` to the checks.doctor probe list so the row is asserted.

Fixes a set -euo pipefail hazard the first VM run caught (exit 1, no
verdict): a no-match grep inside $(...) and a `cond && action` both abort
under set -e — now guarded with || true / || echo 0 / if. Recorded in
MEMORY as a reusable gotcha for writeShellScriptBin scripts.

Verification: V2 PASS — checks.doctor VM test green (fresh build, exit 0;
asserts the hibernate row renders, healthy run stays 0). V1 — ran on real
LUKS+@swap hardware: all three ok rows render (resume set, swap 34G >= RAM,
zram 16G) and the sheet reaches its verdict. V0 bash -n + flake check.

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

pkgs/nomarchy-doctor/nomarchy-doctor.sh

@@ -263,6 +263,62 @@ if [ "$bat_seen" -eq 1 ] && [ "$bat_limited" -eq 0 ]; then
   skip "battery charge limit (none set — charges to 100%)"
 fi
 
+# ── hibernate / sleep (BACKLOG #76) ──────────────────────────────────
+# Read-only: is there a working hibernate path? zram is RAM-only and can't
+# hold a resume image, so hibernation needs a disk swap (partition or file)
+# PLUS resume= wiring; a swapfile additionally needs resume_offset. A
+# swap=0 machine opts out cleanly and this section skips. Never fails the
+# sheet — an absent or under-sized swap is advisory, not a running fault.
+# (|| echo 0 keeps set -euo pipefail happy if a proc file is unreadable.)
+disk_swap_kb=$(awk 'NR>1 && $1 !~ /zram/ {s+=$3} END{print s+0}' /proc/swaps 2>/dev/null || echo 0)
+zram_kb=$(awk 'NR>1 && $1 ~ /zram/ {s+=$3} END{print s+0}' /proc/swaps 2>/dev/null || echo 0)
+ram_kb=$(awk '/^MemTotal:/ {print $2}' /proc/meminfo 2>/dev/null || echo 0)
+
+if [ "${disk_swap_kb:-0}" -gt 0 ]; then
+  if grep -q 'resume=' /proc/cmdline 2>/dev/null; then
+    ok "hibernate: resume device set on the kernel cmdline"
+    # A swapfile also needs resume_offset to locate the image within it.
+    if awk 'NR>1 && $1 !~ /zram/ && $2=="file"{f=1} END{exit !f}' /proc/swaps 2>/dev/null \
+       && ! grep -q 'resume_offset=' /proc/cmdline 2>/dev/null; then
+      warn "swapfile in use but no resume_offset= on the cmdline — resume will fail" \
+           "add boot.kernelParams resume_offset (docs/MIGRATION.md → Enabling hibernation)"
+    fi
+  else
+    warn "disk swap present but no resume= on the kernel cmdline — hibernate won't resume" \
+         "set boot.resumeDevice (docs/MIGRATION.md → Enabling hibernation)"
+  fi
+  if [ "${ram_kb:-0}" -gt 0 ] && [ "$disk_swap_kb" -lt "$ram_kb" ]; then
+    warn "disk swap ($(numfmt --to=iec $((disk_swap_kb * 1024)))) is smaller than RAM ($(numfmt --to=iec $((ram_kb * 1024)))) — a full hibernate image may not fit" \
+         "size swap ≥ RAM (docs/MIGRATION.md → Enabling hibernation)"
+  else
+    ok "hibernate: disk swap ≥ RAM ($(numfmt --to=iec $((disk_swap_kb * 1024))))"
+  fi
+else
+  skip "hibernate (no disk swap — swap=0 opt-out; zram alone can't resume)"
+fi
+
+# zram compressed-RAM swap — the memory-pressure layer oom.nix ships on
+# by default (#76). Its absence on a Nomarchy box means something is off.
+if [ "${zram_kb:-0}" -gt 0 ]; then
+  ok "zram compressed-RAM swap active ($(numfmt --to=iec $((zram_kb * 1024))))"
+else
+  warn "zram swap not active (the default memory-pressure layer)" \
+       "expected on by default — check modules/nixos/oom.nix, then sys-rebuild"
+fi
+
+# Best-effort: a suspend/hibernate failure recorded in the previous boot's
+# kernel log. Needs journal read access; silently no-ops without it. The
+# `|| true` keeps a no-match grep / missing -1 boot from tripping set -e.
+if command -v journalctl >/dev/null 2>&1; then
+  pmerr=$(journalctl -b -1 -k --no-pager 2>/dev/null \
+          | grep -iE 'PM: .*(hibernat|suspend).*(fail|error)|Failed to (hibernate|suspend)' \
+          | tail -n1 || true)
+  if [ -n "$pmerr" ]; then
+    warn "a suspend/hibernate error is in the previous boot's log" \
+         "review: journalctl -b -1 -k -g 'hibernat|suspend'"
+  fi
+fi
+
 # ── verdict ──────────────────────────────────────────────────────────
 echo
 if [ "$fails" -eq 0 ]; then