Implement zero-dependency Wasm binary parser

[bbyalcinkaya]

This PR adds a new zero-dependency binary parser directly in pykwasm that parses Wasm bytecode and produces KAst terms of wasm-semantics. Previously, our parser relied on a py-wasm fork, as described in issue #524
. That dependency has been unmaintained for years and limited our ability to implement fixes, add new features, and stay up-to-date with the Wasm specification. This new parser eliminates the py-wasm dependency.

Changes

• Implement the Wasm binary parser
• Enable all binary parsing integration tests for the new parser
• Add unit tests for individual parsing components
• Removed the unused BlockMetaData field, which was previously used for coverage tracking
• Implement differential testing to compare the old py-wasm-based parser with the new parser

Spec Divergences in the Binary Parser

The parser follows the current WebAssembly spec (WASM 3.0) for decoding, but the K semantics predates several additions. In the places below, bytes are decoded correctly but information is discarded because the semantics has no representation for it.

Blocktype type-index form (instructions.py:47) — A blocktype can be a type index encoded as i33. Only the empty and single-valtype cases are handled; the i33 case raises a parse error. The K semantics block types cannot reference the type section.

Typed select (instructions.py:83) — The typed select variant (0x1C) carries a value-type vector. It is parsed and discarded; the untyped SELECT node is emitted. The K semantics has a single untyped select.

Memory load/store memarg (instructions.py:170) — memarg encodes an alignment hint and an optional memory index alongside the offset. Only the offset is forwarded to the AST; alignment and memory index are discarded. Affects all 23 load/store opcodes. The K semantics models a single memory with offset-only instructions.

memory.size / memory.grow memory index (instructions.py:241) — Both instructions encode a memory index with the multi-memory proposal. It is parsed and discarded; the K semantics has a single implicit memory.

Recursive types (module.py:78) — The spec wraps all type definitions in rectype groups that can be mutually recursive. We only accept singleton groups; actual recursion raises a parse error. The K semantics has no recursive type construct.

Table inline initializer (module.py:119) — The spec allows an optional inline initializer for tables (prefix 0x40 0x00). Encountering it raises a parse error. No counterpart exists in the K semantics.

Address type in limits (types.py:117) — Limit encodings 0x02/0x03 signal 64-bit addressing. The address type is parsed but discarded by every caller (tablesec, memsec, externtype_as_import_desc). The K semantics assumes 32-bit addressing throughout.

Import section externtype (types.py:174) — Import descriptors are encoded as WASM 3.0 externtype but returned as WASM 1.0 ImportDesc nodes. The tag type variant (0x04) raises a parse error. The K ImportDefn sort still matches the WASM 1.0 structure.