chore: comprehensive .gitignore for LaTeX project

.gitignore

@@ -1 +1,41 @@
+# LaTeX build artifacts
+*.aux
+*.log
+*.out
+*.toc
+*.lof
+*.lot
+*.fls
+*.fdb_latexmk
+*.synctex.gz
+*.ent
+*.ptc
+*.nlo
+*.nls
+*.dvi
+*.ps
+*.bbl
+*.blg
+*.run.xml
+*.sav
+*.ilg
+
+# PDFs except main.pdf (tracked)
+*.pdf
+!main.pdf
+
+# Editor swap/backup files
+*~
+.*.swp
+.*.swo
+#*#
+
+# macOS
+.DS_Store
+
+# Build directories
+build/
+_build/
+
+# Opencode
 .opencode/**