feat(display): menu-driven per-output resolution, in-flake

Phase 3 of the in-flake-state philosophy (mirroring night-light + the
keyboard-layout watcher): a System ▸ Display menu item picks an output's
resolution and persists it into the flake instead of a runtime-only tweak.

- rofi.nix: the `display` case reads `hyprctl monitors -j` (auto-skips the
  chooser with one output), lists the output's advertised modes (rounded
  refresh, deduped, highest-first) plus the preferred/highres/highrr
  tokens, applies the pick INSTANTLY via `hyprctl keyword monitor` —
  keeping the output's current position + scale, so only the resolution
  changes — then persists it with `nomarchy-theme-sync set
  settings.monitors.<name> <mode> --no-switch` (no rebuild).
- theme.nix: seed `settings.monitors = {}` (output-name -> "WxH@R") so a
  sparse/older state file still evaluates; exposed via nomarchy.settings.
- hyprland.nix: `resolvedMonitors` overlays settings.monitors onto
  nomarchy.monitors by name — a declared output keeps its other fields
  with only the resolution swapped, an undeclared output (wildcard-only,
  e.g. the laptop panel) becomes a fresh rule. So a later rebuild bakes
  the menu pick into the generated monitor rule — the monitor twin of the
  keyboard graduation. The menu pick wins over a hand-set resolution (it's
  the explicit live action).

Monitor connector names are dot-free, so a direct dotted set-path is safe
(no whole-map read-modify-write like the keyboard watcher needs).

VM-verified via a headless-Hyprland nixosTest (run + removed; too heavy
for a CI gate): the graduation baked the rule into the generated
hyprland.conf, the set/get round-trip persisted, and `hyprctl keyword
monitor` actually changed the reported resolution. Only the interactive
rofi picker isn't headlessly driveable (same caveat as the keyboard watcher).

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

modules/home/hyprland.nix

@@ -59,6 +59,32 @@ let
       ++ lib.optional (m.extra != "") m.extra
     );
 
+  # Menu-remembered per-output resolutions (settings.monitors: output-name ->
+  # "WxH@R", written instantly by the Display menu — see rofi.nix) overlaid onto
+  # the declarative nomarchy.monitors by name: a declared output keeps its
+  # position/scale/etc and only its resolution changes; an output covered solely
+  # by the `,preferred,auto,1` wildcard (e.g. the laptop's built-in panel)
+  # becomes a new rule with default position/scale. The menu writes the in-flake
+  # state with --no-switch (no rebuild) and applies the mode live via hyprctl;
+  # this bakes the same choice on the next rebuild — the monitor twin of the
+  # keyboard graduation. The menu pick wins over a hand-set resolution (it's the
+  # explicit live action); other declared fields are untouched.
+  resOverrides = config.nomarchy.settings.monitors;
+  # Skeleton for an output that's only menu-set (mirrors the monitorType defaults).
+  monitorDefaults = {
+    resolution = "preferred"; position = "auto"; scale = 1;
+    transform = null; mirror = null; bitdepth = null; vrr = null; extra = "";
+  };
+  declaredNames = map (m: m.name) config.nomarchy.monitors;
+  resolvedMonitors =
+    map (m: if resOverrides ? ${m.name}
+            then m // { resolution = resOverrides.${m.name}; }
+            else m)
+        config.nomarchy.monitors
+    ++ lib.mapAttrsToList
+         (name: res: monitorDefaults // { inherit name; resolution = res; })
+         (lib.filterAttrs (name: _: ! lib.elem name declaredNames) resOverrides);
+
   # Candidate layouts offered by the new-keyboard picker: the session
   # layout(s) (nomarchy.keyboard.layout, comma-split for a multi-layout
   # session) plus the extra nomarchy.keyboard.layouts pool. The pool is
@@ -163,7 +189,7 @@ in
       # and Hyprland applies them on hotplug. mkDefault so a downstream
       # `monitor = [...]` replaces the lot (the live ISO uses mkForce too).
       monitor = lib.mkDefault
-        ([ ",preferred,auto,1" ] ++ map monitorRule config.nomarchy.monitors);
+        ([ ",preferred,auto,1" ] ++ map monitorRule resolvedMonitors);
 
       # exec-once is a list at normal priority, so downstream additions
       # CONCATENATE (your autostart runs alongside ours) rather than