Safeguard block breaking and item damage against collectible behavior exceptions (#282)

[Zaldaryon]

Summary

Safeguard block breaking and tool damage against unhandled exceptions thrown by collectible behaviors, resolving #282.

When an external mod behavior throws an unhandled exception during item damage (such as Toolsmith's NullReferenceException in TinkeringUtility.HandleBrokenTinkeredTool when an untracked tinkered tool breaks), the exception escaped ServerSystemBlockSimulation.TryModifyBlockInWorld directly into ServerMain.DispatchClientPacket_mainthread. On dedicated servers, any unhandled exception in client packet dispatch forcibly kicks the player with "Threw an exception at the server" ("An action you or your client did caused an unhandled exception"), aborting block removal and leaving player inventory dirty states out of sync.

This change introduces defensive handling across the breaking pipeline:

1. Collectible.WalkBehaviors wraps behavior invocations in try-catch blocks. If a mod's OnDamageItem throws, the exception is logged to the server logger while allowing vanilla default actions (item damage reduction and slot clearing on zero durability) to complete cleanly.
2. Collectible.OnBlockBrokenWith wraps behavior callbacks in try-catch blocks so third-party mod failures log rather than crashing the breaking sequence.
3. ServerSystemBlockSimulation.TryModifyBlockInWorld wraps OnBlockBrokenWith and block4.OnBlockBroken in a try-catch block. If an exception occurs and the target block was not yet removed, a fallback block break runs so the block is not left in an inconsistent state, and the player is not disconnected.
4. Added Atlas regression scenarios in ItemBreakResilienceScenarios.cs reproducing both failure modes under dedicated server conditions (IsDedicatedServer == true).

Type

• Bug fix
• Performance
• New feature
• Refactor or cleanup
• Docs or build

Checklist

• .\scripts\extract-patches.ps1 ran clean.
• dotnet build VintageStory.slnx -c Release -p:EmbedPatchedFiles=true is green.
• Every vanilla edit has a // Stratum marker.
• No vanilla source committed.
• Tested on a real server start, not just compilation.

Related issues

Fixes #282