fix(diary): default diary_caption_level to 0 (upstream parity)

nuwiki defaulted the per-wiki diary_caption_level to 1; upstream vimwiki's
default is 0 (year captions at the top level, months one below, rather than
nested one deeper). Default it to 0 in wiki_defaults(); still per-wiki
overridable. Render tests pass an explicit level so are unaffected; the
default-value assertion in defaults_carry_vimwiki_per_wiki_keys updated.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

crates/nuwiki-lsp/src/config.rs

@@ -288,7 +288,9 @@ fn wiki_defaults() -> WikiDefaults {
         diary_rel_path: default_diary_rel_path(),
         diary_index: default_diary_index(),
         diary_frequency: default_diary_frequency(),
-        diary_caption_level: 1,
+        // Match upstream vimwiki's `diary_caption_level` default of 0 (year
+        // captions at the top level, months one below). Users override per-wiki.
+        diary_caption_level: 0,
         diary_sort: default_diary_sort(),
         diary_header: default_diary_header(),
         listsyms: default_listsyms(),

crates/nuwiki-lsp/tests/index_and_config.rs

@@ -267,7 +267,7 @@ fn defaults_carry_vimwiki_per_wiki_keys() {
     let cfg = WikiConfig::empty();
     assert_eq!(cfg.index, "index");
     assert_eq!(cfg.diary_frequency, "daily");
-    assert_eq!(cfg.diary_caption_level, 1);
+    assert_eq!(cfg.diary_caption_level, 0); // upstream default
     assert_eq!(cfg.diary_sort, "desc");
     assert_eq!(cfg.diary_header, "Diary");
     assert_eq!(cfg.listsyms, " .oOX");

development/vimwiki-gap.md

@@ -105,8 +105,10 @@ fix site.
   `badd_link` in the links group of both clients (`lua/nuwiki/keymaps.lua`,
   `ftplugin/vimwiki.vim`; docs + README updated). Covered by `map[n].<M-CR>` in
   both keymap harnesses.
-- [ ] **`diary_caption_level` default divergence** — nuwiki `1` vs vimwiki `0`.
-  _Fix:_ `config.rs:291` (and defaults in `lua/nuwiki/config.lua`).
+- [x] **`diary_caption_level` default divergence** — nuwiki defaulted to `1`,
+  upstream `0`. _Fix:_ `wiki_defaults()` in `crates/nuwiki-lsp/src/config.rs` now
+  defaults `diary_caption_level: 0` (year captions top-level, months one below),
+  still per-wiki overridable. Test `defaults_carry_vimwiki_per_wiki_keys` updated.
 - [ ] **`diary_start_week_day`** — **wrongly removed** in `c63ec67`. The removal
   treated it as a server concern and hardwired the weekly diary to ISO-Monday
   (`crates/nuwiki-core/src/date.rs` `monday_of_iso_week`), but choosing which