Add multiACE inventory provider and live source synchronization

[physicsG]

Summary

Implement an open multiACE material-source provider for Snapmaker Orca that reads inventory and live state from the printer-side service and exposes every connected ACE unit and slot through the existing AMS-oriented machine model.

Scope

• Add a provider abstraction for filament-source inventory.
• Implement an initial Moonraker/HTTP/WebSocket-backed multiACE provider.
• Parse versioned capabilities and inventory payloads.
• Support multiple ACE units and stable per-slot source IDs.
• Track RFID metadata, material, subtype, brand, color, remaining quantity, source state, dryer/humidity state, reachable physical heads, and currently loaded head.
• Support manual refresh and live event updates.
• Preserve offline/manual operation when no printer is connected.
• Integrate with the existing Ams, AmsTray, and MachineObject::amsList model where practical.

Proposed code areas

src/slic3r/GUI/multiace/MultiAceClient.hpp
src/slic3r/GUI/multiace/MultiAceClient.cpp
src/slic3r/GUI/multiace/MultiAceSourceProvider.hpp
src/slic3r/GUI/multiace/MultiAceSourceProvider.cpp
src/slic3r/GUI/DeviceManager.hpp
src/slic3r/GUI/DeviceManager.cpp

Acceptance criteria

• All slots from all connected ACE units are visible.
• A source has a stable structured ID such as multiace:<unit>:<slot>.
• Live updates do not silently change project filament definitions.
• RFID refresh updates source metadata and marks stale routes for reconciliation.
• Empty, loading, unloading, error, offline, and ready states are represented.
• Optional capabilities degrade cleanly when absent.
• Disconnect/reconnect does not corrupt inventory state.
• Unit tests cover parser fields, malformed payloads, missing capabilities, and source-state transitions.
• Integration tests use a fake provider and recorded REST/WebSocket fixtures.

Dependencies

This is a foundation for routing, native G-code generation, timing, and optimizer work.

Design references

• doc/multiace_u1_integration_design.md
• doc/multiace_testing_strategy.md