fix: feat: Push3 evolution — diverse seed population (#638)

Add seed-generator.ts module and seed-gen-cli.ts CLI that produce
parametric Push3 variants for initial population seeding.

Variants systematically cover:
  - Staked% thresholds: 80, 85, 88, 91, 94, 97
  - Penalty thresholds: 30, 50, 70, 100
  - Bull params: 4 presets (aggressive → mild)
  - Bear params: 4 presets (standard → very mild)
  - Tax distributions: exponential (seed), linear, sqrt

Total combination space: 6×4×4×4×3 = 1152 variants.
selectVariants(n) samples evenly so every axis is represented.

evolve.sh gains --diverse-seeds flag: when set, gen_0 is seeded with
parametric variants instead of N copies of the same mutated seed.
Remaining slots (if population > generated variants) fall back to
mutations of the base seed.

All generated programs pass transpiler stack validation (33 new tests).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tools/push3-evolution/seed-gen-cli.ts

@@ -0,0 +1,63 @@
+/**
+ * seed-gen-cli.ts — CLI for generating diverse Push3 seed variants (#638).
+ *
+ * Usage:
+ *   tsx seed-gen-cli.ts --count <N> --output-dir <dir>
+ *
+ * Writes N Push3 variant files to <dir>/variant_000.push3 ... variant_NNN.push3
+ * and prints each file path to stdout (one per line).
+ *
+ * The variants are systematically diverse: different staked% thresholds,
+ * penalty thresholds, bull/bear output params, and tax rate distributions.
+ *
+ * Options:
+ *   --count <N>         Number of variants to generate (required, positive integer)
+ *   --output-dir <dir>  Directory to write variant files (required, created if absent)
+ */
+
+import { mkdirSync, writeFileSync } from 'fs';
+import { join } from 'path';
+import { selectVariants, generateSeedVariant } from './seed-generator';
+
+function usage(): void {
+  process.stderr.write('Usage: seed-gen-cli --count <N> --output-dir <dir>\n');
+}
+
+const args = process.argv.slice(2);
+let count: number | undefined;
+let outputDir: string | undefined;
+
+for (let i = 0; i < args.length; i++) {
+  if (args[i] === '--count' && args[i + 1] !== undefined) {
+    count = parseInt(args[++i]!, 10);
+  } else if (args[i] === '--output-dir' && args[i + 1] !== undefined) {
+    outputDir = args[++i];
+  } else {
+    process.stderr.write(`Unknown argument: ${args[i]!}\n`);
+    usage();
+    process.exit(1);
+  }
+}
+
+if (count === undefined || isNaN(count) || count < 1) {
+  process.stderr.write('Error: --count must be a positive integer\n');
+  usage();
+  process.exit(1);
+}
+
+if (!outputDir) {
+  process.stderr.write('Error: --output-dir is required\n');
+  usage();
+  process.exit(1);
+}
+
+mkdirSync(outputDir, { recursive: true });
+
+const variants = selectVariants(count);
+for (let i = 0; i < variants.length; i++) {
+  const text = generateSeedVariant(variants[i]!);
+  const filename = `variant_${String(i).padStart(3, '0')}.push3`;
+  const filepath = join(outputDir, filename);
+  writeFileSync(filepath, text + '\n', 'utf8');
+  process.stdout.write(filepath + '\n');
+}