feat(monitors): main external display, Samsung ultrawide support

monitors.lua picks the main external (Studio Display, else the Samsung
S34CG50 ultrawide, matched on EDID) and reloads the config when it changes.
Workspaces 1-4, the Wacom mapping, and its active-area aspect follow it.
eDP-1 uses auto-right so it sits beside whichever external is connected.

Also unbinds SUPER+RETURN / SUPER+SHIFT+RETURN (terminal and browser live
on SUPER+CTRL+ALT+J/K) and pins the Fastmail/Beeper scratch workspaces'
comments to eDP-1.

monitors.lua

@@ -7,13 +7,55 @@ local omarchy_monitor_scale = 3.2
 hl.env("GDK_SCALE", tostring(omarchy_gdk_scale))
 hl.monitor({ output = "", mode = "preferred", position = "auto", scale = omarchy_monitor_scale })
 
--- Apple Studio Display (DP-4) on the left, laptop panel (eDP-1) on the right.
--- Logical widths at scale 2: 5120/2 = 2560, so eDP-1 starts at x=2560.
-hl.monitor({ output = "eDP-1", mode = "2560x1600@180", position = "2560x0", scale = 2 })
+-- The main external display sits on the left, the laptop panel (eDP-1) to its
+-- right; auto-right puts eDP-1 at the external's logical width (2560 for the
+-- Studio Display at scale 2, 3440 for the ultrawide at scale 1), or at 0x0
+-- when undocked. Apple Studio Display over Thunderbolt, Samsung ultrawide on
+-- a USB-C to HDMI cable from the iGPU (DP alt mode, so it shows up as DP-n;
+-- matched on EDID, so the connector name doesn't matter).
+hl.monitor({ output = "eDP-1", mode = "2560x1600@180", position = "auto-right", scale = 2 })
 hl.monitor({ output = "DP-4", mode = "5120x2880@60", position = "0x0", scale = 2 })
+hl.monitor({ output = "desc:Samsung Electric Company S34CG50 HNTY501103", mode = "3440x1440@100", position = "0x0", scale = 1 })
 
 -- Configure a specific monitor.
 -- hl.monitor({ output = "DP-2", mode = "2560x1440@144", position = "0x0", scale = 1 })
 
 -- Portrait/rotated secondary monitor (transform: 1 = 90°, 3 = 270°).
 -- hl.monitor({ output = "DP-2", mode = "preferred", position = "auto", scale = 1, transform = 1 })
+
+-- Main external display: the first of these that is connected. Workspaces
+-- 1-4 (hypr/hyprland.lua) and the Wacom tablet (hypr/input.lua) follow it.
+-- Entries are Hyprland monitor selectors: a connector name or
+-- desc:<EDID description>.
+local M = {
+  externals = {
+    "desc:Apple Computer Inc StudioDisplay 0x984262A7",
+    "desc:Samsung Electric Company S34CG50 HNTY501103",
+  },
+}
+
+-- The connected main external as (selector, monitor), or nil.
+function M.external()
+  for _, selector in ipairs(M.externals) do
+    for _, monitor in ipairs(hl.get_monitors()) do
+      if selector == monitor.name or selector == "desc:" .. monitor.description then
+        return selector, monitor
+      end
+    end
+  end
+end
+
+-- Workspace rules only create persistent workspaces at config load, so a
+-- change of main external reloads the config rather than patching rules in
+-- place; the reload re-runs every user of M.external() against the new
+-- monitor. Omarchy's reload guard skips it mid package update.
+local loaded = M.external()
+local function reload_on_change()
+  if M.external() ~= loaded then
+    hl.exec_cmd("omarchy-hyprland-reload-guard paused || hyprctl reload")
+  end
+end
+hl.on("monitor.added", reload_on_change)
+hl.on("monitor.removed", reload_on_change)
+
+return M