feat: display unlock conditions on all locked items

All locked items now show players exactly what they need to do next:
- Adventurers: "📜 Complete: [Quest Name]"
- Upgrades: "⚔️ Defeat: [Boss]" or "📜 Complete: [Quest]"
- Equipment (boss drops): "⚔️ Drop: [Boss Name]" instead of generic label
- Bosses: "⚔️ Defeat: [Previous Boss] first" or zone gate boss
- Quests: "📜 Complete: [Prerequisite Quest]"

Also wires adventurer unlocks through quests (militia through dragon_rider
had no unlock path), retroactively applies rewards on existing saves,
syncs boss reward arrays from defaults on load, and removes invalid
rune_stone reference from Forest Giant.

apps/api/src/data/bosses.ts

@@ -49,7 +49,7 @@ export const DEFAULT_BOSSES: Boss[] = [
     essenceReward: 400,
     crystalReward: 20,
     upgradeRewards: ["archmage_1"],
-    equipmentRewards: ["hide_armour", "rune_stone"],
+    equipmentRewards: ["hide_armour"],
     prestigeRequirement: 0,
     zoneId: "verdant_vale",
   },

apps/api/src/data/quests.ts

@@ -8,7 +8,10 @@ export const DEFAULT_QUESTS: Quest[] = [
     description: "Every legend begins somewhere. Send your first adventurer into the field.",
     status: "available",
     durationSeconds: 60,
-    rewards: [{ type: "gold", amount: 500 }],
+    rewards: [
+      { type: "gold", amount: 500 },
+      { type: "adventurer", targetId: "militia" },
+    ],
     prerequisiteIds: [],
     zoneId: "verdant_vale",
   },
@@ -21,6 +24,7 @@ export const DEFAULT_QUESTS: Quest[] = [
     rewards: [
       { type: "gold", amount: 2_000 },
       { type: "essence", amount: 5 },
+      { type: "adventurer", targetId: "apprentice" },
     ],
     prerequisiteIds: ["first_steps"],
     zoneId: "verdant_vale",
@@ -34,6 +38,7 @@ export const DEFAULT_QUESTS: Quest[] = [
     rewards: [
       { type: "crystals", amount: 10 },
       { type: "upgrade", targetId: "global_1" },
+      { type: "adventurer", targetId: "scout" },
     ],
     prerequisiteIds: ["goblin_camp"],
     zoneId: "verdant_vale",
@@ -47,6 +52,7 @@ export const DEFAULT_QUESTS: Quest[] = [
     rewards: [
       { type: "essence", amount: 50 },
       { type: "upgrade", targetId: "click_2" },
+      { type: "adventurer", targetId: "acolyte" },
     ],
     prerequisiteIds: ["haunted_mine"],
     zoneId: "verdant_vale",
@@ -63,6 +69,7 @@ export const DEFAULT_QUESTS: Quest[] = [
       { type: "gold", amount: 15_000 },
       { type: "essence", amount: 20 },
       { type: "upgrade", targetId: "cleric_1" },
+      { type: "adventurer", targetId: "ranger" },
     ],
     prerequisiteIds: [],
     zoneId: "shattered_ruins",
@@ -78,6 +85,7 @@ export const DEFAULT_QUESTS: Quest[] = [
       { type: "gold", amount: 80_000 },
       { type: "essence", amount: 120 },
       { type: "upgrade", targetId: "scout_1" },
+      { type: "adventurer", targetId: "knight" },
     ],
     prerequisiteIds: ["necromancer_tower"],
     zoneId: "shattered_ruins",
@@ -93,6 +101,7 @@ export const DEFAULT_QUESTS: Quest[] = [
       { type: "essence", amount: 300 },
       { type: "crystals", amount: 30 },
       { type: "upgrade", targetId: "mage_1" },
+      { type: "adventurer", targetId: "archmage" },
     ],
     prerequisiteIds: ["crumbling_fortress"],
     zoneId: "shattered_ruins",
@@ -107,6 +116,7 @@ export const DEFAULT_QUESTS: Quest[] = [
     rewards: [
       { type: "gold", amount: 500_000 },
       { type: "crystals", amount: 50 },
+      { type: "adventurer", targetId: "paladin" },
       { type: "adventurer", targetId: "dragon_rider" },
     ],
     prerequisiteIds: ["cursed_library"],