Fix APDU dispatch and metadata parsing edge cases

[abenso]

• APDU improve state machine.
• Metadata proof must fully consume registry, indices and lemmas.
• Swap handle_check_address enforces the same HD-path whitelist as SIGN and validates the declared path length.
• INS_SIGN_RAW requires blobLen to match the buffered payload.
• Display item counter goes through addItemCount; rejects overflow.
• Signed-extension names match via identifier_matches (exact len).
• INS_GET_ADDR rejects unsupported P2 curves.
• GET_ADDR confirm renders 33 bytes for secp256k1, 32 for ed25519.
• Swap chain whitelist uses strcmp instead of hardcoded-length.
• Crypto hash / pubkey buffers MEMZERO'd on every exit path.
• CheckMetadataHash mode byte bounds-checked before deref.
• parseMetadataEntry releases recursion counter on every exit.
• Fuzz harness advances the pageIdx used in the loop condition.