fix: correct equipment stat regressions and purchasable item balance

Full equipment audit revealed 9 items where stats were duplicated,
regressed, or where purchasable items were weaker than free boss drops:

- Void Conduit: 4x → 7x combat (100M essence sink was equal to zone-6 drop)
- Void Edge: 2.75x → 3.25x combat (purchasable was weaker than Celestial Blade)
- Astral Robe: 2.25x → 2.75x gold (boss drop was weaker than Titan's Aegis)
- Philosopher's Stone: 2x → 2.25x click (duplicated Frost Crystal)
- Eternal Flame: 1.15x → 1.25x gold (regressed vs Philosopher's Stone)
- Celestial Focus: 2.5x → 3x click (20M essence sink was weaker than Angel's Halo)
- Abyssal Tome: 3x → 3.75x gold (50M essence sink was equal to Heaven's Mantle)
- Crystal Matrix: 4x → 4.75x gold (20M crystal sink was equal to Sinslayer Aegis)
- Infernal Gem: 3.5x → 4x click (5M crystal sink was identical to Prism Eye)

Closes #54

apps/api/src/data/equipment.ts

@@ -101,7 +101,7 @@ export const defaultEquipment: Array<Equipment> = [
     type:     "weapon",
   },
   {
-    bonus: { combatMultiplier: 2.75 },
+    bonus: { combatMultiplier: 3.25 },
     cost:  { crystals: 500, essence: 2000, gold: 0 },
     description:
       "A blade made of compressed nothingness. It does not cut — it simply unmakes.",
@@ -204,7 +204,7 @@ export const defaultEquipment: Array<Equipment> = [
     type:     "armour",
   },
   {
-    bonus: { goldMultiplier: 2.25 },
+    bonus: { goldMultiplier: 2.75 },
     description:
       "Woven from threads of pure starlight harvested by the Astral Wraith. Income flows like cosmic energy.",
     equipped: false,
@@ -305,7 +305,7 @@ export const defaultEquipment: Array<Equipment> = [
     type:     "trinket",
   },
   {
-    bonus: { clickMultiplier: 2, goldMultiplier: 1.25 },
+    bonus: { clickMultiplier: 2.25, goldMultiplier: 1.25 },
     description:
       "The legendary stone that grants mastery over gold and combat alike.",
     equipped: false,
@@ -316,7 +316,7 @@ export const defaultEquipment: Array<Equipment> = [
     type:     "trinket",
   },
   {
-    bonus: { clickMultiplier: 2.25, goldMultiplier: 1.15 },
+    bonus: { clickMultiplier: 2.25, goldMultiplier: 1.25 },
     description:
       "A flame that has never been extinguished, sealed in crystal by the Phoenix Lord. It burns with the power of rebirth.",
     equipped: false,
@@ -697,7 +697,7 @@ export const defaultEquipment: Array<Equipment> = [
   },
   // ── Purchasable endgame sinks ─────────────────────────────────────────────
   {
-    bonus: { clickMultiplier: 2.5 },
+    bonus: { clickMultiplier: 3 },
     cost:  { crystals: 0, essence: 20_000_000, gold: 0 },
     description:
       "A lens of compressed celestial light that sharpens every strike with divine precision.",
@@ -709,7 +709,7 @@ export const defaultEquipment: Array<Equipment> = [
     type:     "trinket",
   },
   {
-    bonus: { goldMultiplier: 3 },
+    bonus: { goldMultiplier: 3.75 },
     cost:  { crystals: 0, essence: 50_000_000, gold: 0 },
     description:
       "A book written in the language of the deep — reading it aligns your guild's operations with abyssal efficiency.",
@@ -721,7 +721,7 @@ export const defaultEquipment: Array<Equipment> = [
     type:     "armour",
   },
   {
-    bonus: { combatMultiplier: 4 },
+    bonus: { combatMultiplier: 7 },
     cost:  { crystals: 0, essence: 100_000_000, gold: 0 },
     description:
       "A weapon that channels void energy — the absence of resistance makes every strike devastating.",
@@ -733,7 +733,7 @@ export const defaultEquipment: Array<Equipment> = [
     type:     "weapon",
   },
   {
-    bonus: { clickMultiplier: 3.5, goldMultiplier: 1.5 },
+    bonus: { clickMultiplier: 4, goldMultiplier: 1.5 },
     cost:  { crystals: 5_000_000, essence: 0, gold: 0 },
     description:
       "A gem forged in the heart of the Infernal Court — it burns with productivity and righteous fury in equal measure.",
@@ -745,7 +745,7 @@ export const defaultEquipment: Array<Equipment> = [
     type:     "trinket",
   },
   {
-    bonus: { goldMultiplier: 4 },
+    bonus: { goldMultiplier: 4.75 },
     cost:  { crystals: 20_000_000, essence: 0, gold: 0 },
     description:
       "Armour structured around a crystalline lattice of optimal income calculations. Every gold piece finds you faster.",