feat(generate): insert links/tags sections at the cursor line too

Extend the cursor-line insertion from :NuwikiTOC to the other buffer
list generators: :NuwikiGenerateLinks and :NuwikiGenerateTagLinks. They
appended at end-of-file; a fresh section now goes at the cursor line
(with a leading blank), matching :NuwikiTOC. An existing section is still
refreshed in place, and the auto_generate_*-on-save hooks are unaffected
(they only ever replace).

Shared section_insert() helper computes the insert position/block for all
three (cursor line clamped to the document, else the per-command fallback:
top of file for TOC, EOF for links/tags). Clients send the 0-based cursor
line; handlers parse it via parse_uri_line_arg and thread it through
links_edit / tag_links_edit. Rebuild variants pass None.

Tests: links_edit_inserts_at_cursor_line + tag_links_edit_inserts_at_cursor_line.
577 passed, clippy clean, keymap harnesses green. Docs updated.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

crates/nuwiki-lsp/tests/link_health.rs

@@ -597,6 +597,7 @@ fn links_edit_inserts_when_section_absent() {
         1,
         0,
         None,
+        None,
     )
     .expect("edit");
     let te = &edit.changes.unwrap()[&uri][0];
@@ -605,6 +606,37 @@ fn links_edit_inserts_when_section_absent() {
     assert!(!te.new_text.contains("[[Home]]"));
 }
 
+#[test]
+fn links_edit_inserts_at_cursor_line() {
+    // A fresh Generated Links section goes at the cursor line, not the EOF.
+    let src = "= Home =\nbody\nmore\n";
+    let ast = parse(src);
+    let uri = Url::parse("file:///tmp/page.wiki").unwrap();
+    let pages = vec!["A".into()];
+    let edit = ops::links_edit(
+        src,
+        &ast,
+        &uri,
+        "Home",
+        &pages,
+        true,
+        "Generated Links",
+        1,
+        0,
+        None,
+        Some(1),
+    )
+    .expect("edit");
+    let te = &edit.changes.unwrap()[&uri][0];
+    assert_eq!(te.range.start.line, 1);
+    assert_eq!(te.range.start.character, 0);
+    assert!(
+        te.new_text.starts_with("\n= Generated Links ="),
+        "got: {:?}",
+        te.new_text
+    );
+}
+
 #[test]
 fn links_edit_replaces_when_section_present() {
     let src = "= Generated Links =\n- [[Stale]]\n\n= Real =\n";
@@ -622,6 +654,7 @@ fn links_edit_replaces_when_section_present() {
         1,
         0,
         None,
+        None,
     )
     .expect("edit");
     let te = &edit.changes.unwrap()[&uri][0];
@@ -645,6 +678,7 @@ fn links_edit_returns_none_for_empty_page_list() {
         "Generated Links",
         1,
         0,
+        None,
         None
     )
     .is_none());