feat(keywords): add STOPPED keyword

Adds STOPPED alongside TODO/DONE/STARTED/FIXME/FIXED/XXX across the stack:
lexer, AST Keyword enum, HTML renderer (class="stopped"), LSP keyword_str,
and the Vim syntax red group (nuwikiKeywordAttn). Grouped with the
attention/pending keywords (red) for both export and in-editor highlighting.

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

crates/nuwiki-core/src/ast/inline.rs

@@ -14,6 +14,7 @@ pub enum Keyword {
     Fixme,
     Fixed,
     Xxx,
+    Stopped,
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]

crates/nuwiki-core/src/render/html.rs

@@ -502,6 +502,7 @@ impl HtmlRenderer {
             Keyword::Fixme => ("FIXME", "fixme"),
             Keyword::Fixed => ("FIXED", "fixed"),
             Keyword::Xxx => ("XXX", "xxx"),
+            Keyword::Stopped => ("STOPPED", "stopped"),
         };
         write!(w, "<span class=\"{class}\">{label}</span>")
     }

crates/nuwiki-core/src/syntax/vimwiki/lexer.rs

@@ -1141,6 +1141,7 @@ const KEYWORDS: &[(&str, Keyword)] = &[
     ("FIXME", Keyword::Fixme),
     ("FIXED", Keyword::Fixed),
     ("XXX", Keyword::Xxx),
+    ("STOPPED", Keyword::Stopped),
 ];
 
 fn match_keyword(rest: &str) -> Option<(usize, Keyword)> {

crates/nuwiki-core/tests/html_renderer.rs

@@ -205,6 +205,7 @@ fn keyword_spans() {
         ("FIXME x\n", "<span class=\"fixme\">FIXME</span>"),
         ("FIXED x\n", "<span class=\"fixed\">FIXED</span>"),
         ("XXX x\n", "<span class=\"xxx\">XXX</span>"),
+        ("STOPPED x\n", "<span class=\"stopped\">STOPPED</span>"),
     ];
     for (src, expected) in cases {
         let out = render(src);

crates/nuwiki-core/tests/lexer.rs

@@ -450,7 +450,7 @@ fn inline_math_captures_content() {
 // ===== Keywords =====
 
 #[test]
-fn all_six_keywords() {
+fn all_keywords() {
     let cases: &[(&str, Keyword)] = &[
         ("TODO", Keyword::Todo),
         ("DONE", Keyword::Done),
@@ -458,6 +458,7 @@ fn all_six_keywords() {
         ("FIXME", Keyword::Fixme),
         ("FIXED", Keyword::Fixed),
         ("XXX", Keyword::Xxx),
+        ("STOPPED", Keyword::Stopped),
     ];
     for (s, expected) in cases {
         let line = format!("{s} stuff\n");

crates/nuwiki-core/tests/parser.rs

@@ -377,6 +377,7 @@ fn keywords_become_keyword_nodes() {
         ("FIXME", Keyword::Fixme),
         ("FIXED", Keyword::Fixed),
         ("XXX", Keyword::Xxx),
+        ("STOPPED", Keyword::Stopped),
     ];
     for (src, expected) in cases {
         let doc = parse(&format!("{src} stuff\n"));

crates/nuwiki-lsp/src/lib.rs

@@ -1311,6 +1311,7 @@ fn keyword_str(k: nuwiki_core::ast::Keyword) -> &'static str {
         nuwiki_core::ast::Keyword::Fixme => "FIXME",
         nuwiki_core::ast::Keyword::Fixed => "FIXED",
         nuwiki_core::ast::Keyword::Xxx => "XXX",
+        nuwiki_core::ast::Keyword::Stopped => "STOPPED",
     }
 }