Bound cyanosphere urea attribution and correct signaling direction #1614

Causal review of kb/communities/Microcoleus_Massilia_Cyanosphere_Urea_Mutualism.yaml, all3 nodes and2 arrows.
PMID32968213 establishes selective mutualistic growth. Full primary wrad029 directly demonstrates cyanobacterial chemokinetic/chemophobic responses, not Massilia movement toward the cyanobacterium; true Glu chemotaxis was negative. Preserve N-dependent, concentration-dependent bundling and the high-GABA reversal, distinguishing culture from natural-bundle assays. Full wrae246 supports extracellular urea release, growth on low-micromolar urea and coordinated expression, while explicitly acknowledging that the heterotrophic origin in coculture is not absolutely certain. Preserve this strong convergent evidence but qualify the exclusive causal vehicle and unmeasured optimization of nutrient transfer. Repair existing structure; no new nodes/edges. Close only after protected-main merge.

Dedup:901 all-state issue titles/bodies plus ignored/hidden-inclusive scoped local search; read prior1011,1012,596. Self-adversarial finding, not independent approval.