Broken planes cannot fly; repair heals gradually (ISS-089)

- flyPlane 409s a broken plane (health <= 0) before any refuel math — fuel/cash untouched
- engine auto-chain skips chaining when a landing's wear breaks the plane (queue kept intact)
- finishRepairs heals along round(f x 100) each tick; flip to available at exactly 100 on gate pass
- repairPlane no longer jumps health to 100 — it starts the gradual heal
- REMOVED BROKEN_BURN_MULTIPLIER / conditionBurnMultiplier and all burn sites (unreachable now)
- OpenAPI + route comments reworded; unit tests reworked; e2e maintenance.spec.ts per issue
- v0.45.0

lib/game/catalog.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from 'vitest';
-import { BROKEN_BURN_MULTIPLIER, conditionBurnMultiplier, FUEL_DISCOUNT_PER_REP, MAX_FUEL_DISCOUNT, MAX_PLANE_DISCOUNT, PLANE_DISCOUNT_PER_REP, PLANE_TYPES, repRate, STARTER_MODEL } from './catalog';
+import { FUEL_DISCOUNT_PER_REP, MAX_FUEL_DISCOUNT, MAX_PLANE_DISCOUNT, PLANE_DISCOUNT_PER_REP, PLANE_TYPES, repRate, STARTER_MODEL } from './catalog';
 import { STARTING_REPUTATION } from './seed';
 
 // v0.28.0 (ISS-047) — catalog sanity: the progression ladder must stay well-formed as types are added.
@@ -43,21 +43,3 @@ describe('repRate', () => {
     expect(repRate(1_000_000, FUEL_DISCOUNT_PER_REP, MAX_FUEL_DISCOUNT)).toBe(MAX_FUEL_DISCOUNT);
   });
 });
-
-// v0.39.0 (ISS-069) — the broken-state burn factor: ×BROKEN_BURN_MULTIPLIER at/below zero health, exactly 1 above it.
-describe('conditionBurnMultiplier', () => {
-  it('is exactly 1 for any positive health', () => {
-    expect(conditionBurnMultiplier(100)).toBe(1);
-    expect(conditionBurnMultiplier(42)).toBe(1);
-    expect(conditionBurnMultiplier(0.5)).toBe(1); // worn but not broken
-  });
-
-  it('is exactly BROKEN_BURN_MULTIPLIER at and below zero health', () => {
-    expect(conditionBurnMultiplier(0)).toBe(BROKEN_BURN_MULTIPLIER);
-    expect(conditionBurnMultiplier(-3)).toBe(BROKEN_BURN_MULTIPLIER); // defensive — wear clamps at 0, but the gate is <= 0
-  });
-
-  it('pins the broken multiplier at ×1.5', () => {
-    expect(BROKEN_BURN_MULTIPLIER).toBe(1.5);
-  });
-});