Split shared host config into dedicated modules

- Add shared modules for boot, hardware, networking, input, and host defaults
- Move host-specific TOML flags to new option namespaces
- Update SSH and service defaults for the new layout

hosts/legion/host.toml

@@ -4,11 +4,21 @@ id = "45b00123"
 type = "laptop"
 stateVersion = "25.11"
 
+[boot.secureBoot]
+enable = true
+
+[boot.tpmDiskUnlock]
+enable = true
+
+[hardware.graphics]
+vaapi = "nvidia"
+
+[hardware.powerSave]
+enable = true
+
+#[input.homeRowMods]
+#enable = true
+
 [config]
 locale = "uk_UA.UTF-8"
 timeZone = "Europe/Kyiv"
-secureBoot = true
-tpmDiskUnlock = true
-vaapi = "nvidia"
-# laptop.homeRowMods = true
-powerSave = true