balance: early crystal access and smoother production scaling (#173, #174)

Give Troll King 5 crystals (was 0) to signal the crystal economy from
the first boss kill, and halve crystal_focus cost from 100 to 50 so it
is reachable within the first zone's boss chain (#173).

Increase production multiplier base from 1.25 to 1.3 so each prestige
provides more perceptible run-time reduction in the P1-P30 window where
the treadmill effect was most pronounced (#174).

apps/api/test/services/prestige.spec.ts

@@ -131,12 +131,12 @@ describe("calculateProductionMultiplier", () => {
     expect(calculateProductionMultiplier(0)).toBe(1);
   });
 
-  it("returns 1.25 at count 1", () => {
-    expect(calculateProductionMultiplier(1)).toBeCloseTo(1.25);
+  it("returns 1.3 at count 1", () => {
+    expect(calculateProductionMultiplier(1)).toBeCloseTo(1.3);
   });
 
   it("scales exponentially", () => {
-    expect(calculateProductionMultiplier(10)).toBeCloseTo(Math.pow(1.25, 10));
+    expect(calculateProductionMultiplier(10)).toBeCloseTo(Math.pow(1.3, 10));
   });
 });