* Fix exception handling: except* chaining, finally cleanup, RERAISE
- Align except* bytecode chaining
- Fix exception state model and finally handler cleanup
- Fix RERAISE to only pop exception, preserve values below
* Port IR optimization passes from flowgraph.c
- BUILD_TUPLE n + UNPACK_SEQUENCE n elimination
- Dead store elimination within basic blocks
- apply_static_swaps for SWAP reduction
* Add bytecode comparison and disassembly dump scripts
- compare_bytecode.py: compare CPython vs RustPython bytecode output
- dis_dump.py: extract disassembly in normalized JSON format
