Neovim migration — Phase 6: Treesitter and completion (nvim-cmp)

[mattmenefee]

Blocked by

• Neovim migration — Phase 3: Replace Vundle with lazy.nvim #69
• Neovim migration — Phase 4: Replace syntastic with built-in LSP + nvim-lint #70

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Adopt nvim-treesitter for syntax highlighting and structural editing, and nvim-cmp for completion.

Depends on: Phase 3 (lazy.nvim required). Recommended after Phase 4 so LSP is available as a completion source.

Changes

Treesitter

• Add nvim-treesitter/nvim-treesitter with parsers for: ruby, javascript, typescript, tsx, html, scss, yaml, markdown, lua, vim, vimdoc, bash, dockerfile, terraform, python
• Add nvim-treesitter/nvim-treesitter-textobjects for richer text objects
• Drop these syntax/ftplugin plugins (treesitter handles them):
  • pangloss/vim-javascript
  • jelera/vim-javascript-syntax
  • mtscout6/vim-cjsx
  • mxw/vim-jsx (and let g:jsx_ext_required = 0)
  • vim-coffee-script (if Phase 3 didn't already remove it)

Completion

• Add hrsh7th/nvim-cmp with sources: cmp-nvim-lsp, cmp-buffer, cmp-path
• Remove Plugin 'ervandew/supertab' (nvim-cmp handles <Tab> completion) Already removed in Neovim migration — Phase 1: Minimum cutover from MacVim #67 — was incompatible with Neovim 0.12's Lua-callback default mappings. This means there is no tab completion at all until this phase lands.
• Optional: replace Raimondi/delimitMate with windwp/nvim-autopairs (integrates with nvim-cmp)

Acceptance

• Ruby/JS/etc. syntax highlighting visibly richer than current Vimscript regex highlighting
• <Tab> triggers completion menu sourced from LSP/buffer/path
• :TSUpdate keeps parsers fresh
• Legacy syntax plugins removed