search: unified query pipeline with filters, transforms, generators
Extend the pipeline with four stage types composing left-to-right:
Generators: all, match:TERM
Filters: type:, key:, weight:, age:, content-len:, provenance:,
not-visited:, visited: (plus ! negation)
Transforms: sort:(priority|timestamp|content-len|degree|weight), limit:N
Algorithms: spread, spectral, confluence, geodesic, manifold (unchanged)
Duration syntax (7d, 24h, 30m) and glob matching on keys.
CLI auto-detects filter/transform stages and loads full Store;
algorithm-only pipelines keep the fast MmapView path.
Co-Authored-By: ProofOfConcept <poc@bcachefs.org>
e736471d99