feat(lsp): drive checkbox commands from the wiki listsyms palette

Parse editor and export documents with each wiki's configured listsyms,
and make toggle/cycle/reject plus parent-propagation walk the real
palette glyphs instead of the hardcoded ' .oOX'. Falls back to the
default palette when no wiki matches the URI.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

crates/nuwiki-lsp/src/config.rs

@@ -48,9 +48,10 @@ pub struct WikiConfig {
     pub diary_sort: String,
     /// H1 text for the diary index page.
     pub diary_header: String,
-    /// Vimwiki's `g:vimwiki_listsyms`. The 5-character string maps
-    /// fractional progress states for checkboxes; the i-th char (0..=4)
-    /// is the rendered marker for state `i / 4`. Default: `" .oOX"`.
+    /// Vimwiki's `g:vimwiki_listsyms`. A progression of checkbox glyphs
+    /// from "empty" (first) to "done" (last); the lexer recognises these
+    /// glyphs and the toggle/cycle commands walk them. Any length ≥ 2 is
+    /// honoured. Default: `" .oOX"`.
     pub listsyms: String,
     /// When toggling a parent list item, also cascade to descendants.
     pub listsyms_propagate: bool,