feat(links): wire up nuwiki.links.generateForPath (scoped GenerateLinks)

`:VimwikiGenerateLinks <path>` sent nuwiki.links.generateForPath, but the
server had no handler and didn't advertise it — so the scoped form was
silently dropped (only the no-arg form worked). Register and implement it.

The page list is scoped via page_in_scope: a plain `path` is a directory
subtree (the page itself or anything under `<path>/`); a `path` with `*`/`?`
is a glob pattern (upstream's behaviour), matched with export::glob_match
(now pub(crate)). links_generate and the scoped form share
links_generate_scoped, so cursor-line insertion + captions + config all
apply uniformly.

Tests: page_in_scope unit tests (subtree, glob, prefix-sibling, trailing
slash) + COMMANDS advertises both generate forms. 580 passed, clippy
clean, harnesses green. Doc updated with the [path] argument.

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

crates/nuwiki-lsp/tests/commands_links.rs

@@ -32,6 +32,10 @@ fn commands_list_advertises_link_helpers() {
         "nuwiki.link.pasteWikilink",
         "nuwiki.link.pasteUrl",
         "nuwiki.link.catUrl",
+        // Both GenerateLinks forms must be advertised so coc/vim-lsp accept
+        // them (the scoped form was previously sent but unregistered).
+        "nuwiki.links.generate",
+        "nuwiki.links.generateForPath",
     ] {
         assert!(names.contains(&name), "missing: {name}");
     }