feat(13.1): colorize + color_dic → ColorNode renderer

Closes the last pending §13.1 entries:

- **`nuwiki.colorize`** (client-side, Lua + VimL) — wraps the word
  at cursor (or the visual selection on Neovim) in an inline
  `<span style="color:%c">…</span>` template. Matches vimwiki's
  default `color_tag_template`. Bound to `<Leader>wc` in both
  normal and visual mode on both editor paths; the previous
  "deferred" stub is gone.

- **`color_dic` → renderer** — `HtmlConfig` gains a
  `color_dic: HashMap<String, String>` field reading the same key
  out of `initializationOptions` / `didChangeConfiguration`. The
  HTML export path threads it into `HtmlRenderer::with_colors`;
  `ColorNode` now picks `style="color:<value>"` when the colour
  name is in the dict, falling back to the existing
  `class="color-<name>"` when it isn't.

SPEC §13.1 is fully checked off — the table moved from "deferred
sketch" to a per-command status table marking all 11 commands done,
plus a note on the `color_dic` follow-up landing alongside. README's
"Phase 14 list & table edit commands" row now reads ✅ without the
deferred-subset caveat, and the §13.1-blocked text-objects note in
the keymaps section is rephrased as "planned follow-ups".

Tests: 4 new in `phase17_colorize.rs` covering the renderer
fallback when the dict is empty, the inline-style emission for a
listed name, the fallback path for an unlisted name in a populated
dict, and the `initializationOptions` JSON shape. Total 414 Rust
tests pass; clippy clean; keymap harness still 20/20.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

lua/nuwiki/keymaps.lua

@@ -189,8 +189,10 @@ function M.attach(bufnr, mappings)
     map('n', '<Leader>wn', cmd.wiki_goto_page, { desc = 'nuwiki: goto page' }, bufnr)
     map('n', '<Leader>wd', cmd.delete_file,    { desc = 'nuwiki: delete page' }, bufnr)
     map('n', '<Leader>wr', cmd.rename_file,    { desc = 'nuwiki: rename page' }, bufnr)
-    map('n', '<Leader>wc', deferred(':VimwikiColorize'), { desc = 'nuwiki: colorize (deferred)' }, bufnr)
-    map('x', '<Leader>wc', deferred(':VimwikiColorize'), { desc = 'nuwiki: colorize (deferred)' }, bufnr)
+    map('n', '<Leader>wc', function() cmd.colorize() end,
+        { desc = 'nuwiki: wrap word in colour span' }, bufnr)
+    map('x', '<Leader>wc', function() cmd.colorize() end,
+        { desc = 'nuwiki: wrap selection in colour span' }, bufnr)
   end
 
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