JIT Exception Handling

Fix remaining LLVM codegen bugs exposed by the unified invoke/landingpad exception handling architecture (now fully implemented). The core architectural work (Sections 01-03) is complete: ori_panic uses _Unwind_RaiseException, JIT test wrappers use two-layer invoke/landingpad, InvokeIndirect terminators exist in ARC IR and LLVM emission, short-circuit &&/|| is branch-based, and the evaluator uses direct calls with did_panic(). The remaining work is fixing LLVM codegen bugs exposed by the expanded test coverage (Section 04) and running full verification (Section 05).