add phase for colorscheme migration

Paper Tonic colorscheme and custom highlights

- Port Paper Tonic colorscheme as a local plugin.
- Add custom TreeSitter captures for CSS and HTML.
- Verify and extend highlights for plugins and captures.
- Retire legacy highlights and validate performance.

MIGRATION_PLAN.md

@@ -334,25 +334,66 @@ Source of truth for the step-by-step rebuild. Keep this concise and up to date.
 - [x] Persistent folds (via UFO) -- no need, this is no longer required.
 - [x] Note: UFO handles folding; no explicit persistence mechanism needed
 
-## Phase 11 — Cleanup & Validation
+## Phase 11 — Colorscheme Integration
 
 ## Phase 11.1 — Confirm scope and priorities
 - [ ] Confirm scope and priorities for this phase
+- [ ] Decision: Port Paper Tonic colorscheme from `~/projects/nvim-paper-tonic`
+- [ ] Decision: Install as local plugin via lazy.nvim (use `dir = '~/projects/nvim-paper-tonic'`)
+- [ ] Decision: Test first, then extend with missing highlights as needed
+- [ ] Custom TreeSitter captures to verify/define: `@CssClassName`, `@CssIdentifier`, `@DataAttribute`, `@DataAttributeValue`, `@cssPseudoClass`, `@cssNestingSelector`, etc.
 
-## Phase 11.2 — Retire legacy files
+## Phase 11.2 — Install Paper Tonic colorscheme
+- [ ] Create `lua/plugins/colorscheme.lua` with Paper Tonic as local plugin
+- [ ] Set `lazy = false` and `priority = 1000` to load first
+- [ ] Apply colorscheme in config function
+
+## Phase 11.3 — Verify custom TreeSitter highlights
+- [ ] Open HTML/CSS files and verify custom captures have colors
+- [ ] Check if `@CssClassName` (HTML class attributes) matches CSS class selector colors
+- [ ] Check if `@CssIdentifier` (HTML id attributes) matches CSS id selector colors
+- [ ] Check if `@DataAttribute` and `@DataAttributeValue` are distinct
+- [ ] Check CSS-specific captures: `@cssPseudoClass`, `@cssNestingSelector`, `@CssUniversalSelector`, etc.
+
+## Phase 11.4 — Verify plugin highlights
+- [ ] Telescope UI (borders, selection, prompts)
+- [ ] Gitsigns (add, change, delete signs in gutter)
+- [ ] nvim-cmp (completion menu, selected item, kind icons)
+- [ ] LSP diagnostics (ERROR, WARN, HINT, INFO signs and virtual text)
+- [ ] Oil.nvim (if distinctive colors needed)
+
+## Phase 11.5 — Add missing highlights (if needed)
+- [ ] Create `lua/colorscheme-overrides.lua` if custom highlights needed
+- [ ] Define highlights for custom TreeSitter captures not in colorscheme
+- [ ] Define highlights for plugins not covered by colorscheme
+- [ ] Load overrides after colorscheme applies (use autocmd or lazy.nvim config)
+
+## Phase 12 — Cleanup & Validation
+
+## Phase 12.1 — Confirm scope and priorities
+- [ ] Confirm scope and priorities for this phase
+
+## Phase 12.2 — Retire legacy files
 - [ ] Retire legacy Vimscript files (keep for reference until verified)
 
-## Phase 11.3 — Startup performance
+## Phase 12.3 — Startup performance
 - [ ] Validate startup performance (no errors, fast launch)
 
-## Phase 11.4 — Tab workflow validation
-- [ ] Validate tab-per-context workflow with Neo-tree (if used)
-
-## Phase 11.5 — Navigation validation
+## Phase 12.4 — Navigation validation
 - [ ] Validate Telescope navigation + LSP jumps
+- [ ] Validate netrw browsing and preview splits
+- [ ] Validate Oil.nvim file operations
 
-## Phase 11.6 — Language tooling validation
+## Phase 12.5 — Language tooling validation
 - [ ] Validate HTML/PHP/JS/Markdown tooling
+- [ ] Verify LSP (gd, gr, K, diagnostics)
+- [ ] Verify formatting (prettier, phpcbf, stylua)
+- [ ] Verify linting (eslint_d, phpcs, markdownlint)
+
+## Phase 12.6 — Final polish
+- [ ] Review all keymaps and ensure they're documented
+- [ ] Update README.md with final architecture and usage
+- [ ] Clean up any remaining debug code or temporary comments
 
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