build: Packages/ directory with 91 pkgar files + auto-sync script

Packages/ is the canonical binary package repository for Red Bear OS.
Contains stage.pkgar copies of all built packages (91 files).

New scripts:
- local/scripts/sync-packages.sh: syncs built pkgar → Packages/
- make packages-sync: run sync
- make packages-list: list package count

Future: cache-auto will auto-sync to Packages/ after each build.

Makefile

@@ -224,3 +224,5 @@ FORCE:
 # Wireshark
 wireshark: FORCE
 	wireshark $(BUILD)/network.pcap
+packages-sync: ; @bash local/scripts/sync-packages.sh
+packages-list: ; @ls -la Packages/*.pkgar 2>/dev/null | wc -l && echo "pkgar files in Packages/"