Three new composable search stages:
confluence — multi-source spreading activation. Unlike spread (which
takes max from any source), confluence rewards nodes reachable from
multiple seeds additively. Naturally separates unrelated seed groups
since their neighborhoods don't overlap. Params: max_hops, edge_decay,
min_sources.
geodesic — straightest path between seed pairs in spectral space.
At each graph hop, picks the neighbor whose spectral direction most
aligns with the target (cosine similarity of direction vectors).
Nodes on many geodesic paths score highest. Params: max_path, k.
manifold — extrapolation along the direction seeds define. Computes
weighted centroid + principal axis of seeds in spectral space, then
scores candidates by projection onto that axis (penalized by
perpendicular distance). Finds what's "further along" rather than
"nearby." Params: k.
Co-Authored-By: ProofOfConcept <poc@bcachefs.org>