Add song aliases to TOC and fix page numbering

- 82 songs get alias entries (alternate titles/opening lines) shown
  in italic in the TOC, pointing to the same page as the main title
- Front matter (title, foreword, TOC) has no page numbers
- Song pages start at page 1
- Aliases extracted from reference PDF (CL6) TOC by title matching

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

songbook-style.sty

@@ -88,6 +88,7 @@
 \ExplSyntaxOn
 \iow_new:N \g__sb_toc_iow
 \tl_new:N \l__sb_title_tl
+\tl_new:N \l__sb_alias_tl
 \tl_new:N \l__sb_bulibu_tl
 \tl_new:N \l__sb_cl_tl
 \tl_new:N \l__sb_swa_tl
@@ -141,6 +142,18 @@
         { \l__sb_libock_tl }
         { \exp_not:N \pageref { song: \l__sb_num_tl } }
     }
+    % Write alias entry (italic, same page ref, no ref numbers)
+    \tl_set:Nx \l__sb_alias_tl { \songproperty{alias} }
+    \tl_if_empty:NF \l__sb_alias_tl
+    {
+      \iow_now:Nx \g__sb_toc_iow
+      {
+        \exp_not:N \songtocrow
+          { \exp_not:N \textit { \l__sb_alias_tl } }
+          {}{}{}{}{}
+          { \exp_not:N \pageref { song: \l__sb_num_tl } }
+      }
+    }
   }
   % Label MUST be outside guard: measurement pass label is discarded (inside vbox),
   % but the real pass label survives and gets written to .aux