Fuzzing doesn't cover maps holding resources, typed duplicate keys, or malformed lengths #14833

The component_api fuzzer generates maps with valid key types and random string encodings, but a few things aren't covered yet:

• The fuzz type generator has no resources, so maps of own/borrow handles are never fuzzed (the class of bug in Duplicate keys in map<K, V> leak handles #14812).
• The typed path never sees duplicate keys, since Arbitrary for HashMap deduplicates.
• Guests are always well-formed, so out-of-bounds or huge pointer/length pairs are never exercised (the class of bug in map<K, V> allocates memory before validating the guest pointer #14810).
• Nothing cross-checks typed against dynamic (Val) results, and there's no WAVE round-trip fuzzing.

These seem worth closing before map is considered fuzzed in docs/stability-wasm-proposals.md.