feat(keymaps): configurable map_prefix for the wiki command family (P2)

Mirror vimwiki's g:vimwiki_map_prefix. The whole <Leader>w* family was
hardcoded across the map layer; it is now built from a configurable prefix:

- Neovim: `map_prefix` setup() option (default '<Leader>w'), read by
  lua/nuwiki/keymaps.lua (buffer-local) and lua/nuwiki/init.lua (global
  entry points).
- Vim: g:nuwiki_map_prefix, applied via :exe in plugin/nuwiki.vim (global)
  and ftplugin/vimwiki.vim (buffer-local).

Setting a custom prefix relocates <prefix>{w,t,s,i,n,d,r,c,h,hh,ha} and
<prefix><Leader>{w,y,t,m,i}, leaving nothing under the old <Leader>w*.
Non-prefix maps (<CR>, gl*, headers, …) are untouched.

Tests: new test-keymaps-vim-prefix.vim harness (21 cases, wired into
test-keymaps-vim.sh) + map_prefix.relocates_wiki_family in test-keymaps.lua.
Docs: README, doc/nuwiki.txt, lua config comment, vimwiki-gap.md ticked.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lua/nuwiki/config.lua

@@ -13,6 +13,11 @@ M.defaults = {
   syntax         = 'vimwiki',
   log_level      = 'warn',
 
+  -- Prefix for the global/buffer wiki command family (`<prefix>w`,
+  -- `<prefix>t`, `<prefix><Leader>w`, …). Mirrors vimwiki's
+  -- `g:vimwiki_map_prefix`. Vim users set `g:nuwiki_map_prefix` instead.
+  map_prefix     = '<Leader>w',
+
   -- Multi-wiki shape. Each entry honours every per-wiki key the
   -- server understands. Leave nil to fall through to the shorthand
   -- above.

lua/nuwiki/init.lua

@@ -48,15 +48,17 @@ local function _setup_global_mappings()
   if vim.g.nuwiki_no_default_mappings then return end
   local kmap = vim.keymap.set
   local function o(d) return { silent = true, desc = 'nuwiki: ' .. d } end
+  -- Same configurable prefix as the buffer-local maps (vimwiki map_prefix).
+  local p = config.options.map_prefix or '<Leader>w'
 
-  kmap('n', '<Leader>ww',         function() _open(_wiki_index_path(0)) end,             o('wiki index'))
-  kmap('n', '<Leader>wt',         function() _open(_wiki_index_path(0), 'tabedit') end,  o('wiki index (tab)'))
-  kmap('n', '<Leader>ws',         function() require('nuwiki.commands').wiki_ui_select() end, o('pick wiki'))
-  kmap('n', '<Leader>wi',         function() _open(_diary_path(nil)) end,                o('diary index'))
-  kmap('n', '<Leader>w<Leader>w', function() _open(_diary_path(0)) end,                  o('today diary'))
-  kmap('n', '<Leader>w<Leader>y', function() _open(_diary_path(-1)) end,                 o('yesterday diary'))
-  kmap('n', '<Leader>w<Leader>t', function() _open(_diary_path(1)) end,                  o('tomorrow diary'))
-  kmap('n', '<Leader>w<Leader>i', function() require('nuwiki.commands').diary_generate_index() end, o('rebuild diary index'))
+  kmap('n', p .. 'w',         function() _open(_wiki_index_path(0)) end,             o('wiki index'))
+  kmap('n', p .. 't',         function() _open(_wiki_index_path(0), 'tabedit') end,  o('wiki index (tab)'))
+  kmap('n', p .. 's',         function() require('nuwiki.commands').wiki_ui_select() end, o('pick wiki'))
+  kmap('n', p .. 'i',         function() _open(_diary_path(nil)) end,                o('diary index'))
+  kmap('n', p .. '<Leader>w', function() _open(_diary_path(0)) end,                  o('today diary'))
+  kmap('n', p .. '<Leader>y', function() _open(_diary_path(-1)) end,                 o('yesterday diary'))
+  kmap('n', p .. '<Leader>t', function() _open(_diary_path(1)) end,                  o('tomorrow diary'))
+  kmap('n', p .. '<Leader>i', function() require('nuwiki.commands').diary_generate_index() end, o('rebuild diary index'))
 end
 
 -- Global wiki-picker commands so a wiki can be chosen from any buffer before

lua/nuwiki/keymaps.lua

@@ -143,17 +143,22 @@ function M.attach(bufnr, mappings)
     return mappings[group] ~= false
   end
 
-  -- ===== Wiki prefix (`<Leader>w*`) =====
+  -- Configurable wiki command prefix (vimwiki's `g:vimwiki_map_prefix`).
+  -- Every `<prefix>…` mapping below is built from this so users can relocate
+  -- the whole family by setting `map_prefix` in setup().
+  local p = require('nuwiki.config').options.map_prefix or '<Leader>w'
+
+  -- ===== Wiki prefix (`<prefix>*`, default `<Leader>w*`) =====
   if on('wiki_prefix') then
-    map('n', '<Leader>ww', function() cmd.wiki_index(0) end,     { desc = 'nuwiki: open wiki index' }, bufnr)
-    map('n', '<Leader>wt', function() cmd.wiki_tab_index(0) end, { desc = 'nuwiki: open wiki index (tab)' }, bufnr)
-    map('n', '<Leader>ws', cmd.wiki_ui_select, { desc = 'nuwiki: pick wiki' }, bufnr)
-    map('n', '<Leader>wi', cmd.diary_index,    { desc = 'nuwiki: open diary index' }, bufnr)
-    map('n', '<Leader>w<Leader>w', cmd.diary_today,     { desc = 'nuwiki: today' }, bufnr)
-    map('n', '<Leader>w<Leader>y', cmd.diary_yesterday, { desc = 'nuwiki: yesterday' }, bufnr)
-    map('n', '<Leader>w<Leader>t', cmd.diary_today_tab, { desc = 'nuwiki: today in a new tab' }, bufnr)
-    map('n', '<Leader>w<Leader>m', cmd.diary_tomorrow,  { desc = 'nuwiki: tomorrow (vimwiki <Leader>w<Leader>m)' }, bufnr)
-    map('n', '<Leader>w<Leader>i', cmd.diary_generate_index, { desc = 'nuwiki: rebuild diary index' }, bufnr)
+    map('n', p .. 'w', function() cmd.wiki_index(0) end,     { desc = 'nuwiki: open wiki index' }, bufnr)
+    map('n', p .. 't', function() cmd.wiki_tab_index(0) end, { desc = 'nuwiki: open wiki index (tab)' }, bufnr)
+    map('n', p .. 's', cmd.wiki_ui_select, { desc = 'nuwiki: pick wiki' }, bufnr)
+    map('n', p .. 'i', cmd.diary_index,    { desc = 'nuwiki: open diary index' }, bufnr)
+    map('n', p .. '<Leader>w', cmd.diary_today,     { desc = 'nuwiki: today' }, bufnr)
+    map('n', p .. '<Leader>y', cmd.diary_yesterday, { desc = 'nuwiki: yesterday' }, bufnr)
+    map('n', p .. '<Leader>t', cmd.diary_today_tab, { desc = 'nuwiki: today in a new tab' }, bufnr)
+    map('n', p .. '<Leader>m', cmd.diary_tomorrow,  { desc = 'nuwiki: tomorrow (vimwiki <prefix><Leader>m)' }, bufnr)
+    map('n', p .. '<Leader>i', cmd.diary_generate_index, { desc = 'nuwiki: rebuild diary index' }, bufnr)
   end
 
   -- ===== Links =====
@@ -176,12 +181,12 @@ function M.attach(bufnr, mappings)
     map('n', '+',       cmd.normalize_link, { desc = 'nuwiki: wrap word as wikilink' }, bufnr)
     map('x', '+',       function() cmd.normalize_link(true) end,
         { desc = 'nuwiki: wrap selection as wikilink' }, bufnr)
-    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', function() cmd.colorize() end,
+    map('n', p .. 'n', cmd.wiki_goto_page, { desc = 'nuwiki: goto page' }, bufnr)
+    map('n', p .. 'd', cmd.delete_file,    { desc = 'nuwiki: delete page' }, bufnr)
+    map('n', p .. 'r', cmd.rename_file,    { desc = 'nuwiki: rename page' }, bufnr)
+    map('n', p .. 'c', function() cmd.colorize() end,
         { desc = 'nuwiki: wrap word in colour span' }, bufnr)
-    map('x', '<Leader>wc', function() cmd.colorize(nil, true) end,
+    map('x', p .. 'c', function() cmd.colorize(nil, true) end,
         { desc = 'nuwiki: wrap selection in colour span' }, bufnr)
   end
 
@@ -301,9 +306,9 @@ function M.attach(bufnr, mappings)
 
   -- ===== HTML =====
   if on('html_export') then
-    map('n', '<Leader>wh',  cmd.export_current, { desc = 'nuwiki: export to HTML' }, bufnr)
-    map('n', '<Leader>whh', cmd.export_browse,  { desc = 'nuwiki: export + browse' }, bufnr)
-    map('n', '<Leader>wha', cmd.export_all,     { desc = 'nuwiki: export all' }, bufnr)
+    map('n', p .. 'h',  cmd.export_current, { desc = 'nuwiki: export to HTML' }, bufnr)
+    map('n', p .. 'hh', cmd.export_browse,  { desc = 'nuwiki: export + browse' }, bufnr)
+    map('n', p .. 'ha', cmd.export_all,     { desc = 'nuwiki: export all' }, bufnr)
   end
 
   -- ===== Mouse (opt-in via `mappings.mouse = true`) =====