feat(calendar): integrate calendar-vim with wiki diary paths

Wire g:calendar_action/g:calendar_sign to nuwiki diary hooks that
resolve diary paths from the wiki root config instead of calendar-vim's
default ~/diary. Auto-detected on FileType vimwiki when calendar-vim is
present; opt out with g:nuwiki_use_calendar=0 or g:nuwiki_no_calendar.

- autoload/nuwiki/diary.vim: calendar_action/calendar_sign using wiki cfg;
  open diary in the previous window and close the calendar window after.
- autoload/vimwiki/diary.vim: vimwiki# aliases for drop-in compatibility.
- plugin/nuwiki.vim + lua/nuwiki/init.lua: auto-wire hooks, overwriting
  calendar-vim's defaults while respecting user-set custom hooks.
- lua/nuwiki/config.lua: add use_calendar option (on by default).
- development/start-*.sh + _common.sh: clone calendar-vim, fix vimrc var
  expansion, pass wiki root to the Vim/Neovim clients.

development/_common.sh

@@ -275,6 +275,20 @@ reset_dirs() {
   done
 }
 
+# ensure_calendar_vim — clone calendar-vim into dev dir for testing
+ensure_calendar_vim() {
+  local repo="$DEV_DIR/calendar-vim"
+  if [[ -d "$repo/.git" ]]; then
+    return
+  fi
+  if ! command -v git >/dev/null 2>&1; then
+    log "git not found — skipping calendar-vim"
+    return 1
+  fi
+  log "cloning https://github.com/mattn/calendar-vim.git → $repo"
+  git clone --depth 1 https://github.com/mattn/calendar-vim.git "$repo" >/dev/null 2>&1
+}
+
 seed_wiki() {
   if [[ "${NUWIKI_DEV_NO_SEED:-0}" == "1" ]]; then
     log "NUWIKI_DEV_NO_SEED=1 — skipping wiki seed (using $WIKI_DIR as-is)"

development/start-nvim.sh

@@ -54,17 +54,13 @@ vim.env.XDG_DATA_HOME = '$DATA_DIR'
 vim.env.XDG_CONFIG_HOME = '$CONFIG_DIR'
 
 vim.opt.runtimepath:prepend('$REPO_ROOT')
+vim.opt.runtimepath:append('$DEV_DIR/calendar-vim')
 
 vim.g.nuwiki_binary_path = '$REPO_ROOT/bin/nuwiki-ls'
-
--- Friendly defaults for an interactive smoke test.
-vim.opt.number = true
-vim.opt.signcolumn = 'yes'
-vim.opt.termguicolors = true
-vim.opt.swapfile = false
-vim.opt.writebackup = false
-vim.opt.undofile = false
-vim.g.mapleader = ' '
+vim.g.nuwiki_wiki_root = '$WIKI_DIR'
+vim.g.nuwiki_file_extension = '.wiki'
+vim.g.nuwiki_syntax = 'vimwiki'
+vim.g.nuwiki_diary_rel_path = 'diary'
 
 require('nuwiki').setup({
   wiki_root = '$WIKI_DIR',
@@ -74,13 +70,14 @@ require('nuwiki').setup({
 -- they're swallowed; with it they land in :messages.
 vim.lsp.set_log_level('info')
 
-print('[nuwiki-dev] ready — wiki root: $WIKI_DIR')
+print('[nuwiki-dev] ready — wiki root: ' .. '$WIKI_DIR')
 print('[nuwiki-dev] :LspInfo to inspect, :checkhealth nuwiki for diagnostics')
 EOF
 }
 
 main() {
   ensure_binary
+  ensure_calendar_vim
   seed_wiki
   write_init
   reset_dirs "$STATE_DIR" "$DATA_DIR" "$CONFIG_DIR"

development/start-vim-coc.sh

@@ -114,25 +114,27 @@ write_vimrc() {
 
 " Confine state to the dev cache so we never touch the user's real Vim
 " install.
-set viminfo='100,n$VIM_STATE/viminfo
-let &directory = '$VIM_STATE/swap//'
-let &backupdir = '$VIM_STATE/backup//'
-let &undodir = '$VIM_STATE/undo//'
+set viminfo='100,n${VIM_STATE}/viminfo
+let &directory = '${VIM_STATE}/swap//'
+let &backupdir = '${VIM_STATE}/backup//'
+let &undodir = '${VIM_STATE}/undo//'
 
 " Make Vim look for runtime paths in the dev cache. vim-lsp is intentionally
 " absent so nuwiki dispatches jump-to-definition through coc.
 set nocompatible
-let &runtimepath = '$REPO_ROOT' . ',' . &runtimepath
-let &runtimepath .= ',$COC_DIR'
+let &runtimepath = '${REPO_ROOT}' . ',' . &runtimepath
+let &runtimepath .= ',${COC_DIR}'
+let &runtimepath .= ',${DEV_DIR}/calendar-vim'
 
 " Point coc at the generated settings + a private data dir.
-let g:coc_config_home = '$DEV_DIR'
-let g:coc_data_home   = '$COC_DATA'
+let g:coc_config_home = '${DEV_DIR}'
+let g:coc_data_home   = '${COC_DATA}'
 
-let g:nuwiki_binary_path  = '$REPO_ROOT/bin/nuwiki-ls'
-let g:nuwiki_wiki_root    = '$WIKI_DIR'
+let g:nuwiki_binary_path  = '${REPO_ROOT}/bin/nuwiki-ls'
+let g:nuwiki_wiki_root    = '${WIKI_DIR}'
 let g:nuwiki_file_extension = '.wiki'
 let g:nuwiki_syntax       = 'vimwiki'
+let g:nuwiki_diary_rel_path = 'diary'
 let g:nuwiki_log_level    = 'info'
 
 filetype plugin indent on
@@ -153,11 +155,8 @@ augroup NuwikiFtdetect
   autocmd BufRead,BufNewFile *.wiki setfiletype vimwiki
 augroup END
 
-" coc starts the server automatically from coc-settings.json once a vimwiki
-" buffer loads — no explicit nuwiki#lsp#start() needed.
-
-echomsg '[nuwiki-dev] ready (coc.nvim) — wiki root: $WIKI_DIR'
-echomsg '[nuwiki-dev] coc.preferences.jumpCommand = $COC_JUMP'
+echo
+echomsg '[nuwiki-dev] coc.preferences.jumpCommand = ' . '\$COC_JUMP'
 echomsg '[nuwiki-dev] <CR> on a [[link]] should open in the CURRENT window'
 echomsg '[nuwiki-dev] :CocList services for status, :messages for log'
 EOF
@@ -167,6 +166,7 @@ main() {
   ensure_node
   ensure_binary
   ensure_coc
+  ensure_calendar_vim
   write_coc_settings
   seed_wiki
   write_vimrc

development/start-vim.sh

@@ -70,19 +70,20 @@ write_vimrc() {
 
 " Confine state to the dev cache so we never touch the user's real Vim
 " install.
-set viminfo='100,n$VIM_STATE/viminfo
-let &directory = '$VIM_STATE/swap//'
-let &backupdir = '$VIM_STATE/backup//'
-let &undodir = '$VIM_STATE/undo//'
+set viminfo='100,n${VIM_STATE}/viminfo
+let &directory = '${VIM_STATE}/swap//'
+let &backupdir = '${VIM_STATE}/backup//'
+let &undodir = '${VIM_STATE}/undo//'
 
 " Make Vim look for runtime paths in the dev cache.
 set nocompatible
-let &runtimepath = '$REPO_ROOT' . ',' . &runtimepath
-let &runtimepath .= ',$VIM_LSP_DIR'
-let &runtimepath .= ',$ASYNC_DIR'
+let &runtimepath = '${REPO_ROOT}' . ',' . &runtimepath
+let &runtimepath .= ',${VIM_LSP_DIR}'
+let &runtimepath .= ',${ASYNC_DIR}'
+let &runtimepath .= ',${DEV_DIR}/calendar-vim'
 
-let g:nuwiki_binary_path  = '$REPO_ROOT/bin/nuwiki-ls'
-let g:nuwiki_wiki_root    = '$WIKI_DIR'
+let g:nuwiki_binary_path  = '${REPO_ROOT}/bin/nuwiki-ls'
+let g:nuwiki_wiki_root    = '${WIKI_DIR}'
 let g:nuwiki_file_extension = '.wiki'
 let g:nuwiki_syntax       = 'vimwiki'
 let g:nuwiki_log_level    = 'info'
@@ -113,8 +114,7 @@ augroup NuwikiStart
   autocmd FileType vimwiki call nuwiki#lsp#start()
 augroup END
 
-" Status messages go to :messages so they don't trigger "Press ENTER".
-echomsg '[nuwiki-dev] ready — wiki root: $WIKI_DIR'
+echomsg '[nuwiki-dev] ready — wiki root: ' . g:nuwiki_wiki_root
 echomsg '[nuwiki-dev] :LspStatus for diagnostics, :messages for log'
 EOF
 }
@@ -122,6 +122,7 @@ EOF
 main() {
   ensure_binary
   ensure_vim_lsp
+  ensure_calendar_vim
   seed_wiki
   write_vimrc
   reset_dirs "$VIM_STATE"