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>

crates/nuwiki-lsp/src/diary.rs

@@ -202,17 +202,27 @@ fn heading(level: u8, text: &str) -> String {
 /// subheadings so the rendered page mirrors `:VimwikiDiaryGenerateLinks`.
 ///
 /// `caption_level` sets the level of the top caption; the year and month
-/// subheadings nest one and two levels below it. `sort` controls whether
-/// the flat list runs newest- or oldest-first.
+/// subheadings nest one and two levels below it. A `caption_level < 0`
+/// clamps to `0` (nuwiki builds the tree from dates, so upstream's `-1`
+/// "no per-page captions" mode doesn't apply). `months` supplies the
+/// month-number → display name table; an empty slice (or a short list)
+/// falls back to the English `month_name` for any missing slot. `sort`
+/// controls whether the flat list runs newest- or oldest-first. `margin`
+/// is the number of leading spaces before each entry bullet (vimwiki's
+/// `list_margin`).
 pub fn build_index_body(
     entries: &[DiaryEntry],
     diary_rel_path: &str,
     index_heading: &str,
     sort: DiarySort,
-    caption_level: u8,
+    caption_level: i8,
+    months: &[String],
+    margin: usize,
 ) -> String {
+    let base_level = caption_level.max(0) as u8;
+    let pad = " ".repeat(margin);
     let mut out = String::new();
-    out.push_str(&heading(caption_level, index_heading));
+    out.push_str(&heading(base_level, index_heading));
     out.push('\n');
 
     if entries.is_empty() {
@@ -225,8 +235,8 @@ pub fn build_index_body(
         DiarySort::Asc => a.date.cmp(&b.date),
     });
 
-    let year_level = caption_level.saturating_add(1);
-    let month_level = caption_level.saturating_add(2);
+    let year_level = base_level.saturating_add(1);
+    let month_level = base_level.saturating_add(2);
     let mut current_year: Option<i32> = None;
     let mut current_month: Option<u8> = None;
     for e in sorted {
@@ -238,12 +248,17 @@ pub fn build_index_body(
             current_month = None;
         }
         if current_month != Some(e.date.month) {
-            out.push_str(&heading(month_level, month_name(e.date.month)));
+            let label = months
+                .get((e.date.month.saturating_sub(1)) as usize)
+                .map(String::as_str)
+                .filter(|s| !s.is_empty())
+                .unwrap_or_else(|| month_name(e.date.month));
+            out.push_str(&heading(month_level, label));
             out.push('\n');
             current_month = Some(e.date.month);
         }
         out.push_str(&format!(
-            "- [[{}/{}]]\n",
+            "{pad}- [[{}/{}]]\n",
             diary_rel_path.trim_end_matches('/'),
             e.date.format()
         ));
@@ -253,7 +268,8 @@ pub fn build_index_body(
 
 /// Render the diary-index body for the given wiki's currently-indexed
 /// entries. Convenience wrapper around [`build_index_body`] that honours
-/// the wiki's `diary_header`, `diary_sort`, and `diary_caption_level`.
+/// the wiki's `diary_header`, `diary_sort`, `diary_caption_level`, and
+/// `diary_months`.
 pub fn render_index_body(cfg: &WikiConfig, index: &WorkspaceIndex) -> String {
     build_index_body(
         &list_entries(index),
@@ -261,6 +277,8 @@ pub fn render_index_body(cfg: &WikiConfig, index: &WorkspaceIndex) -> String {
         &cfg.diary_header,
         DiarySort::parse(&cfg.diary_sort),
         cfg.diary_caption_level,
+        &cfg.diary_months,
+        cfg.list_margin.max(0) as usize,
     )
 }