Holdings fixes, dev tooling

• Fixed holdings edit Done/Cancel flow — replaces in place, no modal needed.
• Filter inactive holdings from the holdings page.
• Watchlist drag handle fix.
• Back link falls back to href.

Nerdy details

• bin/cloudflare-ddns and bin/public-ip for DDNS management.
• bin/prod improved process/PID management, single instance enforcement.
• bin/dev --ssl support; bin/setup creates alias by default.
• Parameterize port.