[codex] Harden ACE-Step integration for Gradio compatibility

[riversedge]

This branch consolidates the ACE-Step integration work needed for Gradio/API compatibility and adapter handling.

Included changes:

• Gradio client connection fallback across base URLs and Gradio endpoints
• LoRA load recovery when Gradio throws after a successful load event
• Updated generation argument mapping for ACE-Step v1.5
• Source-audio validation for cover/repaint flows
• Duration resolution improvements from Python/Gradio results
• Startup script updates for the Gradio-enabled ACE-Step launch path

The goal is to make the fork behave reliably across the newer ACE-Step/Gradio interface without regressing adapter selection or load behavior.