fix: balance equipment, click_power recipe ceiling, adventurer cost curve

- #141: Already resolved in prior commits (celestial_focus 4.25×,
  void_conduit 10.5×, crystal_matrix 7.5× all exceed free-drop tier)
- #142: Add primal_omega_lens cross-zone click_power recipe at 1.38×,
  matching the eternal_omega combat ceiling and closing the gap above
  the zone-17 cap of 1.25×
- #143: Already resolved in prior commits (elder_bark_shield 1.12×,
  void_fragment_amulet 1.15×, soul_bound_catalyst 1.20× all buffed)
- #144: Raise philosophers_stone click 2.25×→2.5× to differentiate from
  eternal_flame; raise crystal_shard click 1.55×→1.65× so the
  volcanic_forger set trinket beats void_compass (1.6×)
- #145: Militia goldPerSecond already fixed; raise celestial_guard
  baseCost 1.4T→1.8T, smoothing tier 14→15 from 4.67× to 6× and
  removing the jarring tier 15→16 wall (7.14×→5.56×)

apps/api/src/data/adventurers.ts

@@ -177,7 +177,7 @@ export const defaultAdventurers: Array<Adventurer> = [
     unlocked:         false,
   },
   {
-    baseCost:         1_400_000_000_000,
+    baseCost:         1_800_000_000_000,
     class:            "paladin",
     combatPower:      400_000,
     count:            0,