complete neovim 0.12 compatibility audit

AGENTS.md

@@ -8,7 +8,7 @@ This repository is being migrated to a modern, minimal Neovim setup driven by Lu
 - Modern Lua-first config; avoid Vimscript unless explicitly requested.
 - Keep it minimal, fast, and maintainable.
 - Base plugin management on `lazy.nvim` with modular plugin specs.
-- Support Telescope navigation, netrw for tree browsing, previews, and file operations, LSP, Treesitter, Copilot, and sane UX defaults.
+- Support Telescope navigation, netrw for tree browsing, previews, and file operations, LSP, native completion, Treesitter, Copilot, and sane UX defaults.
 - Native project-local configuration via `exrc` + `secure` (no external config plugins).
 
 ## Do Not Reintroduce
@@ -32,12 +32,12 @@ This repository is being migrated to a modern, minimal Neovim setup driven by Lu
     ├── keymaps.lua           -- non-plugin keymaps
     ├── autocmds.lua          -- non-plugin autocommands
     ├── abbreviations.lua     -- insert-mode abbreviations
+    ├── completion.lua        -- native insert-mode and LSP completion
     ├── netrw-config.lua      -- netrw configuration
     ├── utils.lua             -- helpers (only if needed)
     └── plugins/              -- one file per plugin or domain
         ├── telescope.lua
         ├── treesitter.lua
-        ├── cmp.lua
         ├── lsp.lua
         ├── copilot.lua
         ├── ufo.lua
@@ -80,12 +80,12 @@ This repository is being migrated to a modern, minimal Neovim setup driven by Lu
 - Rejected: `folke/neoconf.nvim` (incompatible with Neovim 0.11+ vim.lsp.config API).
 
 ## Required Plugin Categories
-- Core: `nvim-lspconfig`, `nvim-cmp`, `cmp-nvim-lsp`, `cmp-buffer`, `cmp-path`, `LuaSnip`.
+- Core: `nvim-lspconfig`; use Neovim 0.12 native insert-mode/LSP completion and snippets instead of the nvim-cmp stack.
 - Navigation: `telescope.nvim` + `telescope-fzf-native.nvim`; netrw is the sole file explorer.
 - Treesitter: `nvim-treesitter`, `nvim-treesitter-textobjects`, `nvim-ts-autotag`.
-- UX/Editing: `Comment.nvim`, `nvim-surround`, `nvim-autopairs`, `indent-blankline.nvim`, `nvim-ufo`, `undotree`.
+- UX/Editing: `Comment.nvim`, `nvim-surround`, `nvim-autopairs`, `indent-blankline.nvim`, `nvim-ufo`; use Neovim 0.12's native optional `nvim.undotree` package.
 - Git: `gitsigns.nvim`.
-- Copilot: `copilot.lua`, `copilot-cmp`.
+- Copilot: `copilot.lua` with inline suggestions; do not integrate Copilot into the native completion popup.
 - Formatting/Linting: `conform.nvim`, `nvim-lint`.
 - LSP Management: `mason.nvim`, `mason-lspconfig.nvim`, `mason-tool-installer.nvim`.
 
@@ -106,7 +106,7 @@ This repository is being migrated to a modern, minimal Neovim setup driven by Lu
 - Spell & text: `spelllang=en_gb`, custom `listchars`, `showbreak`.
 - Keyword characters: `iskeyword+=$` (for PHP/shell variables), `iskeyword+=-` (for CSS/HTML/config files).
 
-## Current Status (Phase 12 In Progress)
+## Current Status (Phase 13 In Progress)
 - ✅ Phase 1-2: Archive legacy, bootstrap lazy.nvim
 - ✅ Phase 3: Core editing & LSP (native exrc + vim.lsp.config migration complete)
 - ✅ Phase 4: Navigation (Telescope and netrw)
@@ -118,7 +118,8 @@ This repository is being migrated to a modern, minimal Neovim setup driven by Lu
 - ✅ Phase 10: Migrate kept behaviors (abbreviations, templates, custom Treesitter queries)
 - ✅ Phase 11: Modern Paper Tonic colorscheme
 - ⏳ Phase 12: Cleanup and validation (repository cleanup and automated checks complete; interactive workflow checks remain)
-- 📋 Phase 13: Controlled Neovim 0.12.6 upgrade (planned)
+- ⏳ Phase 13: Controlled Neovim 0.12.6 upgrade (configuration audit complete; isolated plugin validation and activation remain)
+- 📋 Phase 13.9: Native Undotree and completion consolidation after activation
 - 📋 Phase 14: Netrw live previews and directory summaries (planned after upgrade)
 
 ## Migration Notes