Restructure modules/shared and update all imports

- Rename modules/hosts/common to modules/shared
- Split shared into home/general, home/linux, and nixos subdirectories
- Update all import paths in lib/ and modules/hosts/
- Fix hardcoded /Users/ path to use config.home.homeDirectory
- Update .sops.yaml path for secrets

modules/hosts/common/files/nvim/lua/plugins/todo-comments.lua

@@ -1,9 +0,0 @@
-return {
-	"folke/todo-comments.nvim",
-	dependencies = { "nvim-lua/plenary.nvim" },
-	opts = {
-		-- your configuration comes here
-		-- or leave it empty to use the default settings
-		-- refer to the configuration section below
-	},
-}