v0.1.1

CI hygiene, dead code removal, and test coverage expansion

- Add cargo clippy -D warnings, cargo test, and mix credo --strict to CI
- Replace crate-level #![allow(dead_code/unused_imports)] with targeted
  per-module allows; remove 5 unused DocumentAccess imports
- Eliminate 3 unwrap() calls in xpath internals
- Remove dead scaffolding: BufferedReader (Strategy B), xpath_map/xmap
- Add 38 tests for previously untested APIs (1334 total)
- Trim changelog to user-visible changes only

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>