Closes the v0.4 series. v0.4.6 = Phase 4.10 (reader-generic `.pth`
inspection, the final cell in the safetensors / NPZ / GGUF / PTH
remote-inspect matrix) plus a series-closer hygiene pass: dual-binary
warning fixed, Cargo.toml metadata relocated, dep tree deduplicated,
quick start widened to surface the four reader-generic entry points.

Verification (publish dry-run gauntlet, all green):
- cargo fmt --check
- cargo clippy --all-targets -- -D warnings
- cargo clippy --all-targets --all-features -- -D warnings
- cargo test --all-features (337 unit + 19 integration suites, 0 fails)
- cargo doc --all-features --no-deps with RUSTDOCFLAGS="-D warnings"
- cargo publish --dry-run --allow-dirty (121 files, 4.3 MiB compressed,
  well under the 10 MiB cap; packaging metadata accepted including the
  now-correctly-placed `categories` and `default-run`)

Next: tag v0.4.6 after this commit's CI run goes green.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>