Fix: Three-Tier Fallback Architecture in adc.py This is related to issue #3089 reported by a user upgraded ADC to 2027

Tier 1 — Public API (ADC v2027+)

• Loads Autodesk.DesktopConnector.API.Public.dll
• Pre-loads WCF assemblies from FOS\Client\SDK + NuGet cache
• Registers AssemblyResolve handler for System.ServiceModel v4.0.0.0
• Currently fails due to NetNamedPipeBinding type not in facade assembly
• Future-proof: if Autodesk fixes the DLL, this tier will start working automatically

Tier 2 — Legacy API (ADC v15–v17)

• Loads from FOS\AddInProcess\Civil3DOE (Revit 2025+) or root (Revit 2023/2024)
• Tests DesktopConnectorService() instantiation during load
• Full file-level operations (lock, unlock, sync, properties)
• Only attempted when Public API DLL is absent (exclusive elif — prevents WCF AppDomain poisoning)

Tier 3 — Legacy API (ADC v15–v17)

• Detects ADC tray process via Process.GetProcesses()
• Scans workspace roots: %USERPROFILE%\DC\ACCDocs, %USERPROFILE%\ACCDocs\
• Parses cloud path schema (Autodesk Forma://org/project/path)
• Resolves to local file by walking workspace directories
• Lock/unlock/sync degrade to no-ops (ADC handles sync at OS level)