Enhances UI with bufferline, diagnostics, and theme

- Integrates plugins for improved buffer management (bufferline, bufdelete) and diagnostics display (trouble).
- Applies the Catppuccin theme for a refreshed visual experience.
- Updates Neovim settings to support new UI elements and enable Nerd Fonts.

lua/custom/plugins/bufdelete.lua

@@ -0,0 +1,18 @@
+-- filepath: /home/kali/.config/nvim/lua/custom/plugins/bufdelete.lua
+-- Bufdelete for properly closing buffers
+-- https://github.com/famiu/bufdelete.nvim
+
+return {
+  'famiu/bufdelete.nvim',
+  event = "VeryLazy", -- lazy load
+  config = function()
+    -- Key mappings to delete buffers
+    vim.keymap.set('n', '<leader>bd', function()
+      require("bufdelete").bufdelete(0, false)
+    end, {noremap = true, desc = "Delete buffer"})
+    
+    vim.keymap.set('n', '<leader>bD', function()
+      require("bufdelete").bufdelete(0, true)
+    end, {noremap = true, desc = "Delete buffer (force)"})
+  end
+}