Drop Julia, assign one primary language per M3 sim spec

Ranked languages per spec by fit; took only the top pick:
- M3a (statistical): R — native stats ecosystem
- M3b (sociological): Prolog — equilibria as constraint satisfaction
- M3c (AMM): Solidity — on-chain-equivalent precision
- M3d (MEV): Fortran — dense PDE/knapsack numerics, no GC
- M3e (tokenomics): Fortran — SDE/VAR matrix loops, same toolchain as M3d
- M3f (consensus): Prolog — Markov/Nash as declarative search
- M3g (microstructure): Zig — tick-level latency, deterministic memory
- Hub: updated to reflect per-spec assignments

Julia removed project-wide: JIT startup cost and large toolchain
not justified when the project isn't going all-in on a single runtime.

core/docs/plans/M3c-amm-liquidity-sims.md

@@ -12,9 +12,9 @@ impermanent loss formula C5 (closed-form: $\text{IL}(r) = \frac{2\sqrt{r}}{1+r}
 simulation parameterization C1.
 
 ## 3. Language & location
-TBD · `src/economy/sims/amm/`. Needs precise fixed-point or arbitrary-precision arithmetic for
-invariant calculations. Solidity for on-chain-equivalent precision; Julia or Octave for
-analytical models.
+TBD · `src/economy/sims/amm/`. **Solidity** — on-chain-equivalent fixed-point arithmetic
+reproduces the exact invariant calculations DEXs execute, eliminating precision-mismatch bugs
+between sim and production contracts.
 
 ## 4. Does / does-not
 - **Does:** simulate constant-product pools with fee parameter $\gamma$: