fix: NPC discovery scans mods built against any version of S1API

[r-melvin]

Summary

A mod built against an S1API version other than the loaded one never has its custom NPCs found, so they never register, and nothing is logged. ReflectionUtils.GetDerivedClasses only scans assemblies that reference the base assembly (#289), and compared full names, which include the version. BigWillyMod 1.0.3 references S1API 3.0.1.0, the loaded one is 3.2.1.0, and the runtime binds it anyway. Of 11 installed mods referencing S1API, only one matched exactly.

The change.

• Binding: a reference binds to the base assembly by simple name and public key token, which is how the runtime binds it.
• Transitive hop: following a reference into another loaded assembly accepts a different version only when exactly one assembly of that name is loaded. Otherwise only an exact identity is followed, as DerivedTypeScanDoesNotFollowSameNameAssembliesWithDifferentIdentities requires.
• Scope: the scan stays bounded to assemblies that reference S1API.

Compatibility

• Public/protected API: none changed. Two new internal static helpers on ReflectionUtils.
• Existing defaults and behavior: assemblies that passed the filter still do; assemblies referencing another S1API version are scanned again, as before the strict check (f8ab166).
• Stable IDs, saves, and network payloads: none touched.

Validation

Mono

dotnet build S1API.sln -c MonoMelon --no-restore -p:AutomateLocalDeployment=false: 0 errors, 0 warnings. dotnet test ... -c MonoMelon: 748 passed (740 on beta plus 8 new).

IL2CPP

dotnet build S1API.sln -c Il2CppMelon --no-restore -p:AutomateLocalDeployment=false: 0 errors, 0 warnings. dotnet test ... -c Il2CppMelon: 728 passed (720 plus 8 new).

Contributor-reported runtime evidence (before maintainer cleanup)

How it was tested. Automated runs on 0.4.7f7 load a save, teleport to each custom NPC, record whether its model is shown and its network state, return to the menu and load again. They used a combined build of #332 to #339.

• Same mods on both runtimes: IL2CPP and Mono "Alternate", with BigWillyMod, The Big Pimpin, Drug Expansion, S1MAPI and SteamNetworkLib. IL2CPP ran without Polyfill, on the game's own interop assembly.
• IL2CPP with about 60 mods: including Polyfill, Siesta and S1UMF.
• Saves: an early save and a late one where The Big Pimpin's intro is played through.

I also played the IL2CPP case by hand.

• Registration: Registered NPC prefab lines for S1API_BigWilly, S1API_DiscoDavey and S1API_BigPimpNPC (The Big Pimpin, built against 3.1.15.0) on both runtimes. Before this change, none of them registered.
• Spawning: all three exist on both loads, and the game's teleport big_willy reaches Big Willy.
• Side effect: mods that were never scanned can now surface their own failures. Drug Expansion's Disco Davey did, which fix: attach NPC data before ConfigurePrefab for dealers and suppliers too #334 fixes.

Documentation

XML <summary> on the new internal helpers. No DocFX changes.

🤖 Generated with Claude Code

Maintainer follow-up

Removed the added NPC prefab registration success log and a redundant test comment. Discovery behavior and failure logging are unchanged. Full solution builds and contract suites pass: 748 Mono, 728 IL2CPP. The runtime evidence above is from the contributor''s earlier combined build, which included the removed log.

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[ifBars]

I pushed adee163 to remove the added NPC registration success log and a redundant test comment. Discovery logic and failure logging are unchanged. Full builds and suites pass: 748 Mono, 728 IL2CPP. I also updated the description so it no longer presents the removed log as part of the current change.

[ifBars]

Tested on 0.4.7f7 Mono and IL2CPP. Three custom NPC classes were discovered and spawned with a test mod whose S1API reference version was set to 3.0.1.0, while the loaded API was 3.2.1.0. This confirms discovery across a reference-version mismatch. Compatibility with older API signatures still depends on the mod.

CI passed. The combined build of #332, #333, #334, #336 and #337 also passed all 770 Mono and 744 IL2CPP tests. Merged into beta.