chore(agent): sync-sweep rule on task completion + apply it; zram user docs

New standing rule (LOOP.md §5 step 4, echoed in AGENTS.md): when a task
ships, grep its number/feature name across agent/ and docs/ and update
or delete every cross-reference it made stale, in the same commit —
including pruning checked-off [x] HARDWARE-QUEUE entries whose outcome
is recorded (journal/ROADMAP; git history is the archive).

First application: BACKLOG PROPOSED groomed (the auto time-of-day theme
pitch was stale — shipped as #79; shipped/promoted placeholder lines
removed; v1.0 pointer rewritten; FUTURE promoted-stub dropped);
HARDWARE-QUEUE pruned of 29 checked entries (363→253 lines) with
dangling references reworded and the prune rule documented in its
header.

Also closes the zram user-doc gap: README §3 now documents the zram
default (zstd/50%/prio 100), hibernation working out of the box on new
installs, and the MIGRATION.md runbook for existing machines.

Verification: V0 (docs/meta only).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

agent/JOURNAL.md

@@ -19,6 +19,21 @@ Template:
 
 ---
 
+## 2026-07-11 — Sync-sweep rule + grooming + zram user docs (human-requested)
+- **Task:** Bernardo: groom stale items and codify the check so they don't
+  recur; close the zram user-doc gap.
+- **Did:** LOOP.md §5 gains step 4 **Sync sweep** (grep item/feature across
+  agent/+docs/ on ship; prune recorded `[x]` queue entries) + an AGENTS.md
+  rule line. Applied it: BACKLOG PROPOSED pruned (auto-theme pitch was
+  stale — shipped as #79; shipped/promoted placeholders removed; v1.0
+  pointer rewritten; FUTURE promoted-stub dropped). HARDWARE-QUEUE pruned
+  29 checked `[x]` entries (363→~250 lines), dangling refs reworded,
+  prune rule in header. README §3 now documents the zram default +
+  hibernation out-of-the-box + MIGRATION pointer.
+- **Verified:** V0 (docs/meta only) — grep sweep for dangling refs clean.
+- **Pending:** night-light geo mode next (same session).
+- **Next suggestion:** wallpapers artifact split (LATER, decided).
+
 ## 2026-07-11 — Vendor-neutral agent docs restructure (human-requested)
 - **Task:** Bernardo: de-vendor the agent instructions (multi-model repo),
   clean stale files, better docs/agent/.claude structure.