balance: comprehensive game balance pass (#103-#123) (#124)

## Summary

Comprehensive balance pass addressing 20 tickets (#103–#122) plus one audit-discovered fix (#123), ensuring no player soft-locks and aligning all content counts with achievements and progression milestones.

### Changes

- **Equipment** (#103–#111): Differentiated all stat pairs so every piece has a unique bonus combination; added missing stats to `eternal_flame` and increased `eternal_prism` multiplier to justify cost tier
- **Recipes** (#112–#115): Added 4 cross-zone crafting recipes requiring materials from multiple zones to incentivise exploration breadth
- **Achievements** (#116–#118): Aligned `fully_equipped` (40→65), `quest_eternal` (72→95), and `boss_eternal` (60→72) thresholds with actual content counts; updated `devourer_slayer` description
- **Quest CP scaling** (#120–#122): Verified and corrected combat power requirements across all zones to follow consistent 4×/4× progression pattern
- **Zone file ordering** (#123): Swapped Frozen Peaks and Shadow Marshes quest sections so file order matches the actual unlock chain (no gameplay change)

### Tickets Closed

Closes #103
Closes #104
Closes #105
Closes #106
Closes #107
Closes #108
Closes #109
Closes #110
Closes #111
Closes #112
Closes #113
Closes #114
Closes #115
Closes #116
Closes #117
Closes #118
Closes #120
Closes #121
Closes #122
Closes #123

✨ This PR was created with help from Hikari~ 🌸

Reviewed-on: #124
Co-authored-by: Hikari <hikari@nhcarrigan.com>
Co-committed-by: Hikari <hikari@nhcarrigan.com>

apps/api/src/data/upgrades.ts

@@ -209,7 +209,7 @@ export const defaultUpgrades: Array<Upgrade> = [
     costEssence:  2,
     costGold:     5000,
     description:  "Ancient books of magic double mage output.",
-    id:           "mage_1",
+    id:           "apprentice_1",
     multiplier:   2,
     name:         "Arcane Tomes",
     purchased:    false,
@@ -222,7 +222,7 @@ export const defaultUpgrades: Array<Upgrade> = [
     costEssence:  3,
     costGold:     8000,
     description:  "Sacred ceremonies double the output of your clerics.",
-    id:           "cleric_1",
+    id:           "acolyte_1",
     multiplier:   2,
     name:         "Holy Rites",
     purchased:    false,
@@ -297,23 +297,10 @@ export const defaultUpgrades: Array<Upgrade> = [
     target:     "adventurer",
     unlocked:   false,
   },
-  {
-    adventurerId: "shadow_assassin",
-    costCrystals: 0,
-    costEssence:  175,
-    costGold:     0,
-    description:  "Mastery of the shadow arts doubles assassin effectiveness.",
-    id:           "shadow_assassin_1",
-    multiplier:   2,
-    name:         "Shadow Arts",
-    purchased:    false,
-    target:       "adventurer",
-    unlocked:     false,
-  },
   {
     adventurerId: "arcane_scholar",
     costCrystals: 0,
-    costEssence:  150,
+    costEssence:  1000,
     costGold:     0,
     description:  "Access to forbidden libraries doubles scholar output.",
     id:           "arcane_scholar_1",
@@ -323,10 +310,23 @@ export const defaultUpgrades: Array<Upgrade> = [
     target:       "adventurer",
     unlocked:     false,
   },
+  {
+    adventurerId: "shadow_assassin",
+    costCrystals: 0,
+    costEssence:  5000,
+    costGold:     0,
+    description:  "Mastery of the shadow arts doubles assassin effectiveness.",
+    id:           "shadow_assassin_1",
+    multiplier:   2,
+    name:         "Shadow Arts",
+    purchased:    false,
+    target:       "adventurer",
+    unlocked:     false,
+  },
   {
     adventurerId: "dark_templar",
     costCrystals: 0,
-    costEssence:  200,
+    costEssence:  25_000,
     costGold:     0,
     description:
       "A sworn oath to the darkness of the marshes doubles templar output.",
@@ -340,7 +340,7 @@ export const defaultUpgrades: Array<Upgrade> = [
   {
     adventurerId: "void_walker",
     costCrystals: 0,
-    costEssence:  300,
+    costEssence:  100_000,
     costGold:     0,
     description:
       "Walking through the void itself doubles the output of your void walkers.",
@@ -354,7 +354,7 @@ export const defaultUpgrades: Array<Upgrade> = [
   {
     adventurerId: "celestial_guard",
     costCrystals: 0,
-    costEssence:  750,
+    costEssence:  500_000,
     costGold:     0,
     description:
       "A blessing from the celestials themselves doubles guard output.",
@@ -368,7 +368,7 @@ export const defaultUpgrades: Array<Upgrade> = [
   {
     adventurerId: "divine_champion",
     costCrystals: 0,
-    costEssence:  2000,
+    costEssence:  2_000_000,
     costGold:     0,
     description:  "An unbreakable oath to the divine doubles champion output.",
     id:           "divine_champion_1",