Rewrite songbook as pure LaTeX project (Carmina Leonis style)

Replace the Kotlin/Gradle multi-module pipeline with a pure LaTeX
songbook using the leadsheets package and LuaLaTeX. Style matches
the Carmina Leonis (CL6) scout songbook: Fraktur titles, chords
above lyrics, metadata at page bottom, reference book footer.

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

songbook-style.sty

@@ -0,0 +1,100 @@
+\NeedsTeXFormat{LaTeX2e}
+\ProvidesPackage{songbook-style}[2026/04/01 Pfadfinder Liederbuch Style]
+
+% --- Core packages ---
+\RequirePackage{fontspec}
+\RequirePackage[ngerman]{babel}
+\RequirePackage[
+  a5paper,
+  top=15mm,
+  bottom=20mm,
+  inner=20mm,
+  outer=12mm
+]{geometry}
+\RequirePackage[hidelinks]{hyperref}
+\RequirePackage{fancyhdr}
+\RequirePackage{xcolor}
+\RequirePackage[minimal]{leadsheets}
+% Pre-mark musicsymbols as loaded to avoid missing musix11 font error
+\ExplSyntaxOn
+\cs_new:cpn {leadsheets-library-musicsymbols-loaded} {}
+\ExplSyntaxOff
+\useleadsheetslibraries{chordnames,chords,shorthands,properties,templates,translations,songs}
+
+% --- Font setup ---
+\setmainfont{TeX Gyre Heros}
+\newfontfamily\frakfont{UnifrakturMaguntia-Book}[Path=fonts/,Extension=.ttf]
+
+% --- Page style: page numbers at bottom-outer, large ---
+\pagestyle{fancy}
+\fancyhf{}
+\fancyfoot[LE]{\large\bfseries\thepage}
+\fancyfoot[RO]{\large\bfseries\thepage}
+\renewcommand{\headrulewidth}{0pt}
+\renewcommand{\footrulewidth}{0pt}
+
+% --- Custom song properties ---
+\definesongproperty{alias}
+\definesongproperty{note}
+\definesongproperty{mundorgel}
+\definesongproperty{pfadfinderliederbuch}
+
+% --- leadsheets settings ---
+\setleadsheets{
+  title-template = songbook,
+  verse/numbered = false,
+  verse/named = false,
+  chorus/named = false,
+  chorus/numbered = false,
+  after-song = \songendsection,
+}
+
+% --- Chord appearance: regular weight, black (matching reference style) ---
+\setchords{
+  format = \small,
+}
+
+% --- Command to render metadata at bottom of song ---
+\newcommand{\songendsection}{%
+  \vfill
+  \ifsongproperty{note}{%
+    {\footnotesize\songproperty{note}\par\smallskip}%
+  }{}%
+  \begingroup\footnotesize
+    \ifsongproperty{lyrics}{%
+      \ifsongproperty{composer}{%
+        Worte: \songproperty{lyrics}\par
+        Weise: \songproperty{composer}\par
+      }{%
+        Worte und Weise: \songproperty{lyrics}\par
+      }%
+    }{%
+      \ifsongproperty{composer}{%
+        Weise: \songproperty{composer}\par
+      }{}%
+    }%
+  \endgroup
+  % Reference book footer
+  \vspace{3mm}%
+  \begingroup\footnotesize
+    \noindent
+    \makebox[0.18\textwidth][c]{MO}%
+    \makebox[0.18\textwidth][c]{PfLB}%
+    \hfill\par\noindent
+    \makebox[0.18\textwidth][c]{%
+      \ifsongproperty{mundorgel}{\songproperty{mundorgel}}{}%
+    }%
+    \makebox[0.18\textwidth][c]{%
+      \ifsongproperty{pfadfinderliederbuch}{\songproperty{pfadfinderliederbuch}}{}%
+    }%
+    \hfill
+  \endgroup
+  \newpage
+}
+
+% --- Song title template: Fraktur title, metadata at bottom ---
+\definesongtitletemplate{songbook}{%
+  {\LARGE\frakfont\songproperty{title}\par}%
+  \addcontentsline{toc}{section}{\songproperty{title}}%
+  \vspace{4mm}%
+}