Return Caps Lock to normal and make Shift + Caps Lock the compose key (#14939)

* Return Caps Lock to normal and make Shift + Caps Lock the compose key

Caps Lock as compose, with both Shifts as Caps Lock, confused too many
people. Stock XKB has no option for compose on the shifted Caps key, so
Omarchy defines one in /etc/xkb, which libxkbcommon reads before the
system rules. The explicit actions keep the Shift level from toggling
Caps Lock. Lone Shift is no longer part of Caps Lock, which leaves it
free for input methods.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Require xkbcli so the keymap check cannot silently skip

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

etc/xkb/rules/evdev

@@ -0,0 +1,6 @@
+// Omarchy's own XKB option. libxkbcommon reads /etc/xkb before the system
+// rules, which supply everything else.
+! include %S/evdev
+
+! option = symbols
+  omarchy:shift_caps_compose = +omarchy(shift_caps_compose)

etc/xkb/symbols/omarchy

@@ -0,0 +1,11 @@
+// Caps Lock stays Caps Lock; Shift + Caps Lock is the Compose key. The actions
+// are explicit so the Shift level never inherits the key's Lock modifier,
+// which would toggle Caps Lock on every compose.
+partial modifier_keys
+xkb_symbols "shift_caps_compose" {
+  key <CAPS> {
+    type[Group1] = "TWO_LEVEL",
+    symbols[Group1] = [ Caps_Lock, Multi_key ],
+    actions[Group1] = [ LockMods(modifiers = Lock), NoAction() ]
+  };
+};