Self-evolving brain implementation

[0SxD]

Context

Sleep cycle + morphogen fitness + knowledge promotion.
Concept paper 03 covers the theory. Implementation pending.
See: docs/specs/SELF_EVOLUTION_LOOP.md

[0SxD]

Corridor validation (Agents_Arcs harsh audit): Self-Evolving Brain pitfalls: (1) Reward Hacking (Goodhart's Law) — fitness on internal metrics will be gamed, needs external holdout sets, (2) AI Slop / Entropy Drift — self-modification amplifies bad patterns, needs static golden principles agent, (3) State Explosion — sleep cycle must wipe context and rebuild from external files.