Adds an NdiGroupSettings record carrying optional comma-separated NDI group lists for the finder and the senders. Extends INdiInterop.CreateFinder / CreateSender with optional groups arguments and populates NDIlib_find_create_t.p_groups and NDIlib_send_create_t.p_groups via P/Invoke. IsoController reads the settings on construction, threads DiscoveryGroups into NdiDiscoveryService and OutputGroups into IsoPipelineConfig, and exposes SetGroupSettingsAsync for runtime updates (group changes apply on next process restart so live pipelines aren't orphaned).
This unblocks the 'transcoder' topology where Teams broadcasts NDI on a private group (e.g. teamsiso-input) and TeamsISO re-emits clean normalized streams on Public — keeping raw, wrong-framerate Teams sources off the production network.
EngineConfig schema is JSON-back-compat: existing config.json files (no NdiGroups field) deserialize with NdiGroups=null and load as NdiGroupSettings.Default. UI surface for these settings comes in a follow-up.
Tests: 72/72 passing (was 69) — added IsoController coverage that group settings are read from ConfigStore on startup, passed to the finder, threaded into per-pipeline config, and round-trip through SetGroupSettingsAsync/Save/Load.
Shipping NDI 6 reports its version as a build banner of the form
NDI SDK WIN64 13:07:00 Jun 2 2025 6.2.0.3
not the 'NDI SDK for Windows v6.x.x.x' format the prefix constant assumed. As a result NdiRuntimeProbe raised a spurious mismatch alert on every supported install. Update ExpectedRuntimeVersionPrefix to 'NDI SDK WIN64' which is the stable architecture token in the new banner; the trailing four-part version remains available for a stricter major-version check if that becomes useful.
The NDI 6 installer sets NDI_RUNTIME_DIR_V6 (and V5/V4 for back-compat) but does not always add the runtime directory to PATH, so a default DllImport(Processing.NDI.Lib.x64) failed with 0x8007007E (DllNotFoundException) on otherwise correctly installed machines, killing both TeamsISO.exe and TeamsISO.Console at preflight.
Add NdiNativeLibraryResolver, registered from NdiNative's static ctor, that resolves the DLL by trying NDI_RUNTIME_DIR_V6 / V5 / V4 in order, NativeLibrary.Load-ing the file from disk before the runtime falls back to its default search algorithm. Static-ctor registration (rather than [ModuleInitializer]) sidesteps CA2255 under TreatWarningsAsErrors and still guarantees the resolver is in place before the first P/Invoke fires.
