docs(review): drift pass over OVERRIDES/TESTING/template README (item 6b)

Slice (b) of the docs review: every factual claim in the three docs
spot-checked against the tree (mkDefault sites, bind priority, CLI
keys, awww naming, preset/wallpaper counts, summer-night's light bar,
live-ISO monitor rule, CI workflow, QEMU GL flags, template steps) —
all held. Two gaps fixed: OVERRIDES §2 predated nomarchy.monitors and
never routed readers to it (added, plus a quick-reference row);
TESTING §1 didn't list the shell-syntax check that §1b says CI runs
(added bash -n).

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

docs/OVERRIDES.md

@@ -39,7 +39,7 @@ in your `home.nix` wins — no `mkForce` needed:
     input.follow_mouse = 0;            # was 1
     input.touchpad.natural_scroll = false;
     misc.disable_splash_rendering = false;
-    monitor = [ "DP-1,2560x1440@144,0x0,1" ];   # replaces the default rule
+    monitor = [ "DP-1,2560x1440@144,0x0,1" ];   # raw rule — replaces the default
     animations.enabled = false;
   };
 
@@ -50,6 +50,11 @@ in your `home.nix` wins — no `mkForce` needed:
 }
 ```
 
+For monitor layout, prefer the friendlier **`nomarchy.monitors`** (a list of
+per-output submodules — resolution/position/scale/rotation — turned into
+Hyprland rules and applied on hotplug; run `nwg-displays` to find the values
+interactively). Assigning `settings.monitor` directly, as above, replaces it.
+
 ### Adding vs. overriding lists
 
 `bind`, `bindel`, `bindl`, `bindm` and `exec-once` are lists kept at normal
@@ -140,6 +145,7 @@ value is theme-owned at normal priority — either change it via the CLI (§1) o
 |---|---|
 | Change gaps / colors / rounding / fonts | `nomarchy-theme-sync set …` or `apply` |
 | Change input / misc / monitor / animations / terminal chrome | plain assignment in `home.nix` |
+| Arrange monitors declaratively | `nomarchy.monitors` (values via `nwg-displays`) |
 | Add keybinds / autostarts | add to the `bind` / `exec-once` list (concatenates) |
 | Replace all keybinds | `bind = lib.mkForce [ … ]` |
 | Hardcode an appearance value against the theme | `lib.mkForce` in `home.nix` |