Improve C# WASM Runtime Binding Loading and Logging - #153

Overview

Follow-up fixes for the C# WASM runtime used in SplashKit Online, focused on
removing unsafe binding logic, improving debuggability, and extending partial
C# binding support.

Issues addressed

• CSP-related failures caused by eval() usage in main.js
• No visibility into which SplashKit bindings failed to resolve
• process_events had no fallback if the binding was ever missing
• DrawCircle had no C# binding at all — filtered out by bindingGenerator.py
  because it takes a color parameter, which isn't supported by JSImport's
  source-generated marshalling

Changes

CSharpWasmExpo/main.js

• Replaced eval(name) with a direct globalThis[name] lookup — avoids CSP
  unsafe-eval restrictions and removes arbitrary code execution
• Added logging for how many/which bindings resolved vs. failed
• Added a no-op fallback for process_events so a missing binding degrades
  gracefully instead of crashing
• Fixed a latent crash where compiler-error parsing assumed a fixed message
  format
• Runtime errors are now also reported back to the IDE via reportError,
  not just logged to console

CSharpWasm/SplashKitBindings.Generated.cs

• Added partial bindings for DrawCircle and RgbaColor, representing
  colour as a packed int (RGBA) since JSImport doesn't support marshalling
  arbitrary structs like SplashKit's color type
• Verified via local build (buildAndCopy.sh) after correcting an initial
  uint return type to int (uint isn't marshallable — SYSLIB1072)

Known follow-up (not fixed here)

While testing, found that OpenWindow has no C# binding either — same root
cause (Window is in the generator's unsupported_types filter). The C#
backend currently has no way to explicitly open a window through bindings.
Worth its own follow-up item.

Testing

Built and ran locally via CSharpWasm/buildAndCopy.sh + npm run server.
Confirmed in browser DevTools console:

• [SKO C# Runtime] Resolved 777/908 SplashKit bindings.
• [SKO C# Runtime] .NET WASM runtime ready.
• No eval/CSP-related errors
• DrawCircle/RgbaColor compile and execute without error via a test
  C# program (using ClearScreen() in place of OpenWindow due to the
  gap noted above)