feat(themes): wallpapers split — 94 MB of runtime-only images leave the flake source

The split line is consumption time: palette JSONs, previews and
per-theme overrides are read at Nix eval and stay in-repo (~3 MB);
wallpapers are runtime-only (swww via nomarchy-state-sync, never read
at eval) and move to the pinned nomarchy-wallpapers non-flake input
(git.bemagri.xyz/bernardo/Nomarchy-Wallpapers @ 803b48d, all 24 slugs).

New overlay drv nomarchy-default-themes merges the two: repo themes
copied, <slug>/backgrounds symlinked from the input, build FAILS if any
theme JSON lacks non-empty backgrounds — the drift guard for the
two-repo dance. nomarchy-state-sync's wrapper now points straight at
the merged store path (no in-package copy): the package drops from
~94 MB to 32.6 KiB and the wallpapers source appears exactly once in
any system closure, ISO included — offline promise intact. Downstream
custom wallpapers still win ($NOMARCHY_PATH/themes is checked first),
and an explicit state.json wallpaper path still works.

checks re-pointed at the merged tree (theme-wholeswap,
state-sync-validate, auto-theme); theme-contrast and airplane stay on
./themes (JSON/text only). import-palettes.py + README updated;
ROADMAP § Faster switches marked shipped; LATER now carries only the
pre-built-variants follow-on. Also files #151 (v1 launch plan, [human])
with measured history numbers: the 107 MiB pack is 94 MB wallpaper
blobs; all 848 text commits pack to ~15-20 MiB — recommendation
recorded to filter-repo at the GitHub move, not fresh-start.

Verification: V2 — nix flake check --no-build green; theme-wholeswap,
state-sync-validate, auto-theme VM check, downstream-template-home all
green; wallpapers store path exactly once in the state-sync closure;
`list` works from a scratch state dir. V3 queued: live wallpaper render
+ bg-next + custom-override precedence after next pull (HARDWARE-QUEUE).
Lock gained exactly the one input node. Implementation by a Sonnet
subagent; design and review on Fable.

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

agent/HARDWARE-QUEUE.md

@@ -39,6 +39,12 @@ Everything else below stays open; order is convenience, not a gate.
       toast appears. Same relogin answers #149's question (does the Waybar
       unit still race Hyprland IPC on a cold relogin without linger?).
       **Fail:** the panel stays lit inside the shut lid (the #148 symptom).
+- [ ] **Wallpapers-split live smoke (dev box)** — after the next
+      `nomarchy-pull` + `nomarchy-home`: wallpaper still renders at session
+      start; `SUPER+SHIFT+T` (bg next) cycles; `readlink` of the applied
+      image resolves into the `nomarchy-wallpapers` store path, not the
+      repo. **Pass:** all three. A custom wallpaper dropped in
+      `~/.nomarchy/themes/<slug>/backgrounds/` must still win.
 - [ ] **#115 suspend-then-hibernate (laptop with hibernate/resume wired)** —
       after system rebuild: Preferences shows **Suspend then hibernate (on)**
       (hidden if `CanHibernate=no`). Confirm: