🏛 Modernize Neovim config: Vimscript → Lua, replace deprecated plugins

[ladislas]

Summary

Modernize this Neovim config: migrate from Vimscript to Lua, replace deprecated/abandoned plugins, switch plugin manager, and update the repo structure.

Motivation

This config hasn't been touched in years. It uses vim-plug (vendored submodule), deprecated plugins (YouCompleteMe, Deoplete, Denite, LanguageClient-neovim, neoyank), and is entirely in Vimscript. Neovim v0.12 is installed locally — the config should take advantage of native LSP, treesitter, and the modern Lua plugin ecosystem.

Audit Results

Immediate removals (deprecated / abandoned / replaced by better alternatives)

Plugin	Reason
YouCompleteMe	Requested removal; deprecated; replaced by nvim-cmp + LSP
Deoplete	Deprecated by author
LanguageClient-neovim	Deprecated; nvim has built-in LSP client
Denite	Deprecated by author
neoyank	Only useful with Denite
CompleteParameter	LSP handles parameter completion
vim-polyglot	Replaced by treesitter
cpp-enhanced-highlight	Treesitter handles C/C++
swift.vim	Treesitter handles Swift
vim-ansible-yaml	Treesitter + LSP handle YAML
vim-livedown	Unmaintained
vim-multiple-cursors	Unmaintained; native alternatives exist

Replacements

Old	New	Reason
vim-plug (vendored submodule)	lazy.nvim	Self-bootstrapping, Lua-native, faster
NERDTree + nerdtree-git-plugin	neo-tree.nvim	Lua, better UX, git integration built-in
vim-startify	alpha-nvim	Lua, lighter
vim-gitgutter	gitsigns.nvim	Lua, faster, more features
Denite (fuzzy finder)	fzf-lua	Fast, uses fzf binary
UltiSnips	LuaSnip	Lua-native, better nvim-cmp integration
vim-airline	lualine.nvim	Lua, lighter
rainbow	rainbow-delimiters.nvim	Maintained fork
gruvbox (Vimscript)	gruvbox.nvim	Lua port
nord-vim	nordic.nvim or drop	Lua port

Keep as-is

vim-surround, vim-commentary, vim-repeat, vim-endwise, vim-easy-align, vim-fugitive, undotree, editorconfig-vim, auto-pairs, vim-bufonly, vim-bufkill, vim-pandoc (+ syntax), vim-snippets (custom)

New additions

Plugin	Purpose
lazy.nvim	Plugin manager
nvim-cmp	Autocompletion engine
LuaSnip	Snippet engine
mason.nvim	LSP/DAP/linter installer
nvim-lspconfig	LSP configuration
nvim-treesitter	Syntax highlighting + textobjects
fzf-lua	Fuzzy finder
neo-tree.nvim	File explorer
gitsigns.nvim	Git gutter signs
lualine.nvim	Status line
alpha-nvim	Start screen
rainbow-delimiters.nvim	Rainbow parentheses
gruvbox.nvim	Colorscheme
which-key.nvim	Keybinding discovery (nice-to-have)

Acceptance Criteria

• Branch renamed from master to main
• Dead code removed (big.vim, autoload/ submodule, plug.vim.old)
• Config migrated to Lua (init.lua + modular lua/ structure)
• Plugin manager switched to lazy.nvim (self-bootstrapping, no submodule)
• All deprecated plugins removed and replaced with Lua equivalents
• YouCompleteMe removed per request
• Key bindings and behavior preserved from original config
• README updated
• Spell files and after/syntax/make.vim preserved

[ladislas]

All 9 acceptance criteria met. Closing as complete.