Adapt the Whale dependency and IR tests to format 4 #868

Motivation

Official Whale master is ff38baf14dc5076ae5eea8ac78e8bc422d00b8c2 after wavefnd/Whale#242 and wavefnd/Whale#243. It adds bounded interpretation, tracked stack memory and Uninit, and prints format 4. Wave Cargo.lock still resolves 020d2a4 and tests/whale_backend.rs asserts format 3.

Scope

Update the official master lock resolution deliberately, inspect the changed verifier/instruction/initialization API, and adapt Wave IR assertions and round-trip tests. Keep current lowering semantics and unsupported diagnostics intact. This is dependency integration, not a native execution feature.

Difficulty: medium.

Completion criteria

• Build and test with the recorded official revision.
• Round-trip supported Wave modules through the format-4 reader/verifier.
• Keep LLVM default and report actual support accurately.