Update colorscheme configuration and cleanup legacy files

- Updated `lua/plugins/colorscheme.lua` to load `paper-tonic-modern`
- Moved old `paper-tonic/` directory to `legacy/paper-tonic-original/`
- Validated full config reload; all highlight groups load correctly
- No separate overrides needed with modern implementation

MIGRATION_PLAN.md

@@ -432,10 +432,17 @@ Source of truth for the step-by-step rebuild. Keep this concise and up to date.
 - indent-blankline and ufo use subtle grays for non-intrusive UI
 
 ## Phase 11.9 — Update plugin configuration
-- [ ] Update `lua/plugins/colorscheme.lua` to use paper-tonic-modern
-- [ ] Remove old Paper Tonic reference
-- [ ] Remove colorscheme-overrides.lua (no longer needed)
-- [ ] Test full config reload
+- [x] Update `lua/plugins/colorscheme.lua` to use paper-tonic-modern
+- [x] Remove old Paper Tonic reference
+- [x] Remove colorscheme-overrides.lua (no longer needed)
+- [x] Test full config reload
+
+**Notes**:
+- `lua/plugins/colorscheme.lua` already updated to load `paper-tonic-modern`
+- Old `paper-tonic/` directory moved to `legacy/paper-tonic-original/` (archived)
+- No `colorscheme-overrides.lua` existed (not needed with modern implementation)
+- Full config reload tested: Normal ✓, DiagnosticError ✓, TelescopeNormal ✓, GitSignsAdd ✓
+- Colorscheme loads correctly: `vim.g.colors_name = 'paper-tonic-modern'`
 
 ## Phase 11.10 — Validation and polish
 - [ ] Test all primary languages (Lua, PHP, HTML, CSS, JS, Markdown)

README.md

@@ -155,6 +155,12 @@ Record every decision here with a short rationale. Append new entries; do not re
   - **Oil.nvim highlights**: Bold directories, status colors for permissions (read=green, write=orange, execute=blue), operation colors
   - **indent-blankline**: Subtle grays for guides and scope
   - **nvim-ufo**: Subtle backgrounds for folds with preview support
+- 2025-12-11: Colorscheme Phase 11.9:
+  - **Plugin configuration updated**: `lua/plugins/colorscheme.lua` loads `paper-tonic-modern`
+  - **Cleanup**: Moved old `paper-tonic/` directory to `legacy/paper-tonic-original/`
+  - **Validation**: Full config reload tested - all highlight groups load correctly
+  - **Colorscheme integration**: Native Neovim colorscheme at `colors/paper-tonic-modern.lua`
+  - **No overrides needed**: Modern implementation doesn't require separate override file
 
 ## Project-Local Configuration (design)