Review (Hoshe) caught that the MAX_ATTRACTORS cap sorted by global strength,
and RiverMouth's normalized strength (accum/max_accum) is tiny — so on a
realistic body 108 river mouths produced 0 surviving RiverMouth attractors,
violating D-209 ('RiverMouth: always high-value') and starving #955 placement.
Replace the global-strength cap with group-by-type + round-robin so every
present type keeps representation (strongest-first within each type).
Deterministic. New test river_mouths_survive_cap locks it in.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>