v1.1.6

release: 1.1.6 with Value bignum-tag fix, test and script hardening

Library
- Decode a bignum tag (2 or 3) around anything but a byte string as an
  ordinary tag in Value and other deserialize_any targets. Such items are
  well-formed and Value encodes them (e.g. 2(null) as c2f6), but decoding
  failed the whole item: 12,053 of 174,897 generated well-formed items.

Tests
- Cross-check generated and mutated items across slice/reader decoding
  (Value and eight typed targets, error kinds and offsets), validation,
  diagnostic notation read back as CDN, both canonical encoders and
  sizing. This is how the bignum-tag bug was found.
- Replace the split-UTF-8 vectors (7f61e261829461acff also fails on a
  stray 0x94 array header) with 7f62e28261acff, the euro sign split.
- Drive the futures adapters one byte per poll so their short-read and
  short-write loops run; route every roundtrip() call through sizing,
  fixed-buffer, slice, reader and Value paths.
- Share test doubles in tests/it/util.rs, one synthetic tag-protocol
  deserializer instead of five, and one RFC 8949 Appendix A table that
  also checks diagnostics, CDN read-back and the reader path.

Examples and docs
- Use validate_slice and the slice sequence iterator for in-memory
  buffers, as AGENTS.md and the cookbook recommend; CI runs every example.
- Document the release check, shared test doubles and CLI map order.

Scripts and workflows
- Windows installer: edit the raw user Path registry value so other
  %VARIABLE% entries keep REG_EXPAND_SZ, update it in-process through one
  script with -Remove, and let the uninstaller finish after deleting its
  own directory.
- Homebrew: commit only the formula with a one-off identity, leaving a
  local tap's config and staged changes alone; reject malformed checksums.
- Add scripts/check-release-version.sh and run it on tags before release
  builds and crates.io publishing.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>