Clean up config: fix broken plugin specs, dedupe options/keymaps, drop dead code

- lspsaga: custom keys lived outside config(), so setup({}) ran empty and
  they never worked; moved into setup() and updated to the plugin's current
  option schema (finder_action_keys/definition_action_keys/move_in_saga
  are stale names in the installed version)
- catppuccin: fixed a stray `as = "catppuccin"` key left outside the plugin
  table; wrapped as { "catppuccin/nvim", name = "catppuccin" }
- options: consolidated the three competing sources (vimrc, init.lua,
  custom/options.lua) into custom/options.lua alone; hlsearch/wrap were
  silently landing opposite to what init.lua's own comments said, purely
  from require-order. custom/options.lua now loads first in the require
  chain since colorizer.lua and others need termguicolors set before their
  own setup() runs
- removed duplicate keymaps that were dead on arrival due to load order
  (<leader>rn, <leader>sf/sg/sh, jj, <leader>y, mapleader x3, manual
  C-h/j/k/l vs vim-tmux-navigator)
- removed dead code: smart_format, root_dir/fallback_root_dir, toggleterm's
  unused _LAZYGIT_TOGGLE/_NODE_TOGGLE/_PYTHON_TOGGLE globals, unused local
  cmp, stale commented blocks, lua/custom/startup.lua
- removed unused plugins: mini.icons, telescope-dap.nvim,
  startup-nvim/startup.nvim (malformed spec, never actually required),
  plus leftover ALE globals with no ALE plugin installed
- vim.loop.* -> vim.uv.*, vim.diagnostic.goto_prev/next ->
  vim.diagnostic.jump({count=...}) for 0.12.5
- guard vim.treesitter.start() at the top of init.lua: the system's
  bundled Lua highlight query is currently ahead of the available
  tree-sitter-lua grammar (a packaging skew, confirmed nvim-treesitter is
  fully up to date), which was throwing on every Lua buffer and taking
  omnifunc/foldexpr down with it; now falls back to regex highlighting
  with a single notify instead

Verified end-to-end against a real Neovim 0.12.5 headless instance with a
fresh plugin install: no load errors, lspsaga's custom keys now actually
apply, and the treesitter guard was confirmed against the real environment.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013jVh2Lhn386JAvjSFCHUhn

lua/custom/keymaps.lua

@@ -1,5 +1,3 @@
-vim.g.mapleader = ' '
-
 local keymap = vim.keymap
 
 keymap.set('i', 'jj', '<ESC>')
@@ -56,12 +54,6 @@ keymap.set('n', '<leader>gh', ':DiffviewFileHistory %<CR>', { silent = true })
 -- toggleterm
 keymap.set('n', '<M-1>', '<cmd>ToggleTerm direction=horizontal<cr>', { silent = true })
 
--- vim-sneak
--- keymap.set('n', 'f', '<Plug>Sneak_s', { silent = true })
--- keymap.set('n', 'F', '<Plug>Sneak_S', { silent = true })
--- keymap.set('n', 's', 's', { silent = true })
-
-
 -- easymotion
 keymap.set('n', '<leader>f', '<Plug>(easymotion-prefix)', { silent = true })
 keymap.set('n', '<leader>fs', '<Plug>(easymotion-sn)', { silent = true })