refactor(usb): make device topology descriptor-driven

[pvurda]

Summary

• replace global endpoint/interface assumptions with a portable per-device USB topology descriptor
• validate topology direction, endpoint numbers, transfer masks, altsetting compatibility, duplicate endpoints, and managed-interface ordering
• validate every required endpoint against the real USB descriptors before claiming interfaces or creating ALSA state
• claim unique secondary interfaces, preserve original altsettings, and roll back in reverse order
• migrate Ploytec to interface 0 playback / interface 1 capture / managed MIDI input without changing IDs or packet processing

No Xone:43C USB ID or runtime support is added. The existing 40/80-frame discrepancy remains deliberately unchanged. This PR is stacked on #1.

Topology contract

The shared descriptor represents full endpoint addresses, interface/altsetting ownership, allowed bulk/interrupt/isochronous transports, and whether MIDI belongs to Ozzy. Isochronous configurations validate structurally but Linux probe returns -EOPNOTSUPP until an isochronous data plane exists. Unmanaged MIDI is excluded from interface claims and ALSA rawmidi creation.

Validation

• 43,140 TAP assertions across 18 cases
• GCC and Clang with ASan/UBSan
• Linux module build with W=1 against kernel 6.14 locally
• CI gates preserve exactly 0a4a:ffdb, ffd2, ffdd, ff4d, and ffad
• no residual intf2, global num_interfaces, midi_in_ep, or legacy PCM endpoint fields
• checkpatch: zero errors

Rollback behavior

All descriptors are checked before claims. A partial claim or altsetting failure restores configured interfaces in reverse order and releases only interfaces actually claimed by Ozzy. Physical disconnect avoids USB control operations once the device is detached.

[pvurda]

Final stacked CI is green: https://github.com/pvurda/Ozzy/actions/runs/32918815537

Passed gates:

• kernel module builds on 5.15, 6.8, and 6.14 with W=1
• GCC and Clang protocol/topology tests under ASan/UBSan
• 43,140 TAP assertions
• exact five-device USB ID preservation gate
• changed-line checkpatch with zero errors

All three module artifacts were downloaded and their modinfo names verified as snd_usb_ozzy.