feat(display): per-profile workspace→output pins (item 15c)

A display profile can now pin workspaces to outputs:

  docked = {
    monitors   = [ … ];
    workspaces = { "1" = "DP-3"; "9" = "eDP-1"; };
  };

The bare list-of-monitors shape still works (either-type; hyprland.nix
normalizes — coercedTo refuses list-of-submodule sources). Pins bake as
Hyprland `workspace` rules from the active profile and apply instantly
on `nomarchy-display-profile apply`: keyword sets the session rule,
moveworkspacetomonitor moves open workspaces over. Pins from a
previously applied profile linger in-session until reload/rebuild
(hyprctl can only add) — inert if the output is absent, noted in the
applier.

V1: flake check green (checks.display-profiles now asserts
workspaceRule) + scratch-downstream eval: baked settings carry both
rule sets, the generated applier has the keyword+dispatch pairs
(bash -n), match/list correct with mixed shapes. V3 queued in
HARDWARE-QUEUE (rides the dock test). Item 15 complete — deleted.

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

modules/home/monitor-rules.nix

@@ -24,6 +24,11 @@ rec {
       ++ lib.optional (m.extra != "") m.extra
     );
 
+  # A profile's workspace pinning ({ "1" = "DP-3"; }) -> a Hyprland
+  # `workspace` rule. Only the active profile's pins are rendered
+  # (hyprland.nix); a workspace rule naming an absent output is inert.
+  workspaceRule = ws: out: "${ws}, monitor:${out}";
+
   # The full overlay, three layers:
   #
   #  1. base (nomarchy.monitors) with the ACTIVE display profile's entries