fix(parity): close the 2026-06-02 re-audit config/command findings

Implements the remaining fourth-pass findings (gap doc updated):

- list_margin: rework to upstream's buffer-side meaning. Drop the
  nuwiki-only HTML em-margin (renderer field/method + render_page_html
  param removed) and prepend max(0, list_margin) leading spaces to every
  generated bullet in build_toc_text / build_links_text /
  build_tag_links_text / diary::build_index_body; headings stay at col 0.
  From<RawWiki> derives 0 for markdown wikis when unset. Negatives can't
  resolve 'shiftwidth' server-side, so they collapse to zero indent
  (documented divergence).

- diary_months: per-wiki Vec<String> (default 12 English names), threaded
  into the diary-index month labels; missing/empty slots fall back to the
  English name.

- diary_caption_level: widen u8 -> i8 so vimwiki's -1 (min: -1) parses;
  build_index_body clamps < 0 to base tree level 0.

- VimwikiRemoveDone: regain upstream's -range. All four defs are now
  -bang -range, dispatched via remove_done(bang, range, l1, l2) in both
  clients: ! -> whole buffer, explicit range -> new list_remove_done_range
  ({range:[l1-1,l2-1]}), else current list. Server remove_done_edit gained
  an Option<(u32,u32)> range that filters whole-doc victims by start line.

markdown_header_style is deferred: the generators emit vimwiki syntax only
(caption_line never writes markdown headers), so there's no markdown header
to attach the style to. Logged as the "generated-content is vimwiki-only"
intentional divergence pending a later markdown generated-content effort.

Tests: list_margin indent, markdown list_margin-0 default, diary_months
custom + fallback, negative caption_level clamp/parse, ranged remove-done
(server + both keymap harnesses). 553 lsp/core tests pass; clippy clean.

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

ftplugin/vimwiki.vim

@@ -84,7 +84,7 @@ if !has('nvim')
   command! -buffer -range -nargs=1 VimwikiChangeSymbolTo       call nuwiki#commands#list_change_symbol_range(<q-args>, <line1>, <line2>)
   command! -buffer -range -nargs=1 VimwikiListChangeSymbolI    call nuwiki#commands#list_change_symbol_range(<q-args>, <line1>, <line2>)
   command! -buffer -nargs=1 VimwikiChangeSymbolInListTo call nuwiki#commands#list_change_symbol(<q-args>, 1)
-  command! -buffer -bang  VimwikiRemoveDone            if <bang>0 | call nuwiki#commands#list_remove_done_all() | else | call nuwiki#commands#list_remove_done() | endif
+  command! -buffer -bang -range VimwikiRemoveDone      call nuwiki#commands#remove_done(<bang>0, <range>, <line1>, <line2>)
   command! -buffer -range VimwikiRemoveSingleCB       call nuwiki#commands#list_remove_checkbox()
   command! -buffer        VimwikiRemoveCBInList       call nuwiki#commands#list_remove_checkbox_in_list()
   command! -buffer -range -nargs=+ VimwikiListChangeLvl       call nuwiki#commands#list_change_lvl(<line1>, <line2>, <f-args>)
@@ -170,7 +170,7 @@ if !has('nvim')
   command! -buffer        Nuwiki2HTMLBrowse            call nuwiki#commands#export_browse()
   command! -buffer -bang  NuwikiAll2HTML               if <bang>0 | call nuwiki#commands#export_all_force() | else | call nuwiki#commands#export_all() | endif
 
-  command! -buffer -bang  NuwikiRemoveDone             if <bang>0 | call nuwiki#commands#list_remove_done_all() | else | call nuwiki#commands#list_remove_done() | endif
+  command! -buffer -bang -range NuwikiRemoveDone       call nuwiki#commands#remove_done(<bang>0, <range>, <line1>, <line2>)
   command! -buffer -range NuwikiRemoveCheckbox         call nuwiki#commands#list_remove_checkbox()
   command! -buffer        NuwikiRemoveCheckboxInList   call nuwiki#commands#list_remove_checkbox_in_list()
   command! -buffer -range -nargs=+ NuwikiListChangeLvl        call nuwiki#commands#list_change_lvl(<line1>, <line2>, <f-args>)
@@ -433,7 +433,7 @@ command! -buffer -range        VimwikiDecrementListItem    lua require('nuwiki.c
 command! -buffer -range -nargs=1 VimwikiChangeSymbolTo       lua require('nuwiki.commands').list_change_symbol_range(<q-args>, <line1>, <line2>)
 command! -buffer -range -nargs=1 VimwikiListChangeSymbolI    lua require('nuwiki.commands').list_change_symbol_range(<q-args>, <line1>, <line2>)
 command! -buffer -nargs=1 VimwikiChangeSymbolInListTo lua require('nuwiki.commands').list_change_symbol(<q-args>, true)
-command! -buffer -bang  VimwikiRemoveDone            lua require('nuwiki.commands')[('<bang>' == '!') and 'list_remove_done_all' or 'list_remove_done']()
+command! -buffer -bang -range VimwikiRemoveDone      lua require('nuwiki.commands').remove_done('<bang>' == '!', <range>, <line1>, <line2>)
 command! -buffer -range VimwikiRemoveSingleCB       lua require('nuwiki.commands').list_remove_checkbox()
 command! -buffer        VimwikiRemoveCBInList       lua require('nuwiki.commands').list_remove_checkbox_in_list()
 command! -buffer -range -nargs=+ VimwikiListChangeLvl        lua require('nuwiki.commands').list_change_lvl(<line1>, <line2>, <f-args>)
@@ -519,7 +519,7 @@ command! -buffer -nargs=*        NuwikiSplitLink   split | lua require('nuwiki.c
 command! -buffer -nargs=*        NuwikiVSplitLink  vsplit | lua require('nuwiki.commands').follow_link_or_create()
 command! -buffer        NuwikiTabnewLink  tabnew | lua require('nuwiki.commands').follow_link_or_create()
 command! -buffer        NuwikiTabDropLink lua require('nuwiki.commands').follow_link_drop()
-command! -buffer -bang  NuwikiRemoveDone             lua require('nuwiki.commands')[('<bang>' == '!') and 'list_remove_done_all' or 'list_remove_done']()
+command! -buffer -bang -range NuwikiRemoveDone       lua require('nuwiki.commands').remove_done('<bang>' == '!', <range>, <line1>, <line2>)
 command! -buffer -range NuwikiRemoveCheckbox         lua require('nuwiki.commands').list_remove_checkbox()
 command! -buffer        NuwikiRemoveCheckboxInList   lua require('nuwiki.commands').list_remove_checkbox_in_list()
 command! -buffer -range -nargs=+ NuwikiListChangeLvl        lua require('nuwiki.commands').list_change_lvl(<line1>, <line2>, <f-args>)