fix dispatcher hyphen bug in 4 more services

setup.sh's run_service() looks up install_<name> using the literal
hyphenated registered name, not an underscore-converted one. borg-backup,
calibre-web, gaming-backup, and stirling-pdf all used underscored function
names and were therefore uninstallable ("has no install_<name>"). Same
fix already applied to ai-gpu/ai-stack; this closes out the rest of the
repo-wide audit.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Nb2vJ8W7bHKx1JXVvpCraH

services/stirling-pdf.sh

@@ -181,7 +181,7 @@ fi
 
 register_service stirling-pdf utilities "PDF toolkit — merge, split, compress, OCR (Stirling PDF)" 8070
 
-install_stirling_pdf() {
+install_stirling-pdf() {
     require_docker || return 1
     log_info "Installing Stirling PDF..."
 
@@ -313,4 +313,4 @@ MD
 }
 
 # Run immediately when executed directly (deferred until after function definition)
-[[ "${_RUN_STANDALONE:-0}" == 1 ]] && install_stirling_pdf
+[[ "${_RUN_STANDALONE:-0}" == 1 ]] && install_stirling-pdf