bcs_dart

Added

• Example at example/bcs_dart_example.dart.

Changed

• Expanded the package description and corrected the repository URL.
• Formatting and static-analysis cleanup across the package (no API changes).

Synced to f898c13.

Behavior changes

• Bcs.map now sorts entries by their serialized key bytes before writing, for canonical key ordering. Maps that were not already in canonical key order now produce different (correct) bytes.
• Hex.decode (and fromHEX) now reject non-hex input (sign characters, whitespace, other non-[0-9a-fA-F] characters) with a FormatException instead of silently producing corrupt bytes.

Fixes

• BcsWriter.ensureSizeOrGrow grows the buffer to fit a single write larger than allocateSize instead of throwing.
• ulebDecode throws on a truncated buffer (continuation bit with no more bytes) and on values exceeding MAX_SAFE_INTEGER.
• Bcs.enumeration read bounds-checks the variant index and throws a descriptive error for an unknown variant.

Added

• Top-level compareBcsBytes (lexicographic byte comparison).
• Bcs.byteVector() — a fast vector<u8> that reads/writes raw bytes (same wire bytes as vector(u8())).
• BcsWriter.writeBytes(Uint8List) bulk write.
• Top-level isSerializedBcs(Object?) type guard; bcs_type.dart is now re-exported from the bcs.dart barrel.
• BcsType.transform accepts one-directional transforms (input/output are now optional).

• Fix: remove flutter dependency
• Refactor: minor