Stale 0..5 range from pre-2026-04-08 9-level code. Only test paths call
this cold-path fallback, but the stale range was a latent foot-gun and
would mislead anyone reading the code (per feedback_trust_code_not_docs).
Fix: sample dir ∈ [0,3), mag ∈ [0,3), ord ∈ [0,3), urg ∈ [0,3) and encode
as `dir*27 + mag*9 + ord*3 + urg`, matching MEMORY.md 4-branch DQN
architecture (81 factored actions).
Per Track 4 E1 triage tech-debt flag.
2a7005f29a