Measure migrator budgets off the final scoped prompt

Author: TheGreatAxios

src/agent/prompt-sizes.test.ts

@@ -42,8 +42,8 @@ const CHAR_BUDGET: Record<DirectorId, number> = {
   // 2000 allowance, ceiling to 100.
   prober: 15800,
   // CL-7671 scope-honesty sentences grew migrator past the 12300-char
-  // placeholder: measured-max + 2000 allowance, ceiling to 100.
-  migrator: 12800,
+  // placeholder: measured-max (11202) + 2000 allowance, ceiling to 100.
+  migrator: 13300,
 };
 
 const BYTE_BUDGET: Record<DirectorId, number> = {
@@ -74,8 +74,8 @@ const BYTE_BUDGET: Record<DirectorId, number> = {
   // 3000 allowance, ceiling to 100.
   prober: 16800,
   // CL-7671 scope-honesty sentences grew migrator past the 13400-byte
-  // placeholder: measured-max + 3000 allowance, ceiling to 100.
-  migrator: 13900,
+  // placeholder: measured-max (11258) + 3000 allowance, ceiling to 100.
+  migrator: 14300,
 };
 
 function budgetMessage(