Cut 18.1.0 and bump the package version in pyproject.toml,
CITATION.cff, and uv.lock.

Minor: `build-fullmap --taxon-allowlist` adds an opt-in, source-derived
fullmap restricted to the checked-in top-100 experimental taxon
allowlist (#149), recording a deterministic `META.taxon_allowlist`
identity and never reusing the unfiltered prebuilt; the same PR stops
Rust token QC from rejecting `inchikey`, so InChIKey terms are indexed
in both raw normalized and CURIE form. Default fullmap builds, the
prebuilt download path, and existing Python callers are unchanged. Also
ships the category-vocabulary fix behind bare `biolink:Association`
edges (#151): `CATEGORY_OVERRIDES` makes the `GenomicEntity` mixin
nameable in `avoid`/`prioritize` and as a `category_override` key,
`filter_and_rank` drops categories the `Categories` enum cannot name
when `avoid` is set, and the `--qc` study stage now fails the build on
edges demoted to bare `Association` when a section declares a
`category_override` (`study_kgx` gained `category_override_declared`).

Changelog:
- Versioned the Unreleased section as 18.1.0 - 2026-09-14.
- Added the missing `### Added` entry for #149, which merged after
  18.0.0 and would otherwise have shipped unmentioned.
- Added the (#151) PR links to the three Fixed entries.

Docs: none needed here; #149 and #151 already updated docs/cli.md,
docs/fullmap.md, and docs/api/fullmap.md on main.

Testing:
- make check -> passed
- uv run ruff check . -> All checks passed!
- uv run ruff format --check . -> 88 files already formatted
- cargo fmt --check --manifest-path rust/Cargo.toml -> passed
- uv run pyright -> 0 errors, 0 warnings, 0 informations
- uv run pytest -> 1335 passed, 43 skipped
- cargo test --manifest-path rust/Cargo.toml -> 137 passed, 1 ignored
- cargo clippy --manifest-path rust/Cargo.toml --all-targets
  -- -D warnings -> passed
- uv lock --check -> passed