feat(i18n): proper multilingual input

Use fcitx5 to switch between different inputs. Installed mozc-ut for
Japanese input with the bepo layout, as well as fcitx5-chinese to load
table-defined layouts for the IPA/X-SAMPA input method.

Currently, mozc_server and fcitx5 need to be launched by the
compositor (only Hyprland for now), auto-launching from module options
needs to be implemented in the future.

users/phundrak/home.nix

@@ -157,16 +157,19 @@
         vcs.jj.signing.enable = true;
       };
       fullDesktop = true;
-      file."${config.home.homeDirectory}/.ssh/allowed_signers" = {
-        enable = true;
-        text = lib.strings.join "\n" (
-          map (file: let
-            content = lib.strings.trim (builtins.readFile file);
-            parts = lib.strings.splitString " " content;
-            email = lib.lists.last parts;
-          in "${email} namespaces=\"git\" ${content}")
-          (lib.filesystem.listFilesRecursive ./keys)
-        );
+      file = {
+        ".XCompose".source = ./XCompose;
+        "${config.home.homeDirectory}/.ssh/allowed_signers" = {
+          enable = true;
+          text = lib.strings.join "\n" (
+            map (file: let
+              content = lib.strings.trim (builtins.readFile file);
+              parts = lib.strings.splitString " " content;
+              email = lib.lists.last parts;
+            in "${email} namespaces=\"git\" ${content}")
+            (lib.filesystem.listFilesRecursive ./keys)
+          );
+        };
       };
     };