Add recursive component resolution for assembly dependencies

Assemblies reference other assemblies and parts internally; a flat
single-level copy into raw/ left Creo unable to load models ("Dati di
input non completi"). AssemblyComponentScanner heuristically extracts
component codes embedded as readable strings inside the otherwise
binary .asm files; each candidate is validated against the index (which
filters out scan noise), copied into raw/, and if it's itself an
assembly, queued for the same treatment until the whole tree resolves
to PRT leaves. PrtMancantiForm reports what was found and copied.

Also ignore Creo Distributed Batch job files (*.dxc).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

.gitignore

@@ -28,3 +28,4 @@ publish/
 /*.csv
 /raw/
 /step/
+*.dxc