Remove RUST_STUB_MODE: generate real transpiled exchange code

- Remove RUST_STUB_MODE flag entirely from rustTranspiler.ts
- Exchange-specific methods now get fully transpiled JS→Rust bodies
  instead of `{ Value::Undefined }` stubs
- Base Exchange class methods still use stubs (runtime not ready)
- Inherited base methods removed from exchange traits (available via
  Exchange supertrait) to avoid E0034 ambiguity
- Fix TryStatement to emit try block inline (catch as comment)
- Add AST visitors: SpreadElement, ArrowFunction, FunctionExpression,
  TemplateLiteral, ForOf/ForIn, SwitchStatement
- Fix dispatch call matching (case-insensitive API method names)
- Fix method call generation: use UFCS for overrides, instance calls
  for inherited methods
- Add BoolExt trait, From<i32>, From<Value> for serde_json::Value
- Add Precise static methods, Math methods, Array::is_array
- Add runtime stub methods for pre-delimiter Exchange.js functions
  (load_markets, omit, iso8601, etc.)
- Fix argument count table for safe* methods and other utilities
- Make Exchange require ValueTrait supertrait for self.get() access

Result: binance.rs goes from 499 stub methods to 0 stubs, with 202
real transpiled functions across 13,477 lines.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: Herklos