feat: Remove banned mana types (life, blood, wood, mental, force) and lifesteal

- Remove life, blood, wood, mental, force mana types from ELEMENTS
- Remove all spells using banned mana types
- Remove lifesteal from all remaining spells and effects
- Update guardian perks to remove lifesteal mentions
- Remove research skills for banned spell types
- Update tests to reflect new element structure
- Add BANNED CONTENT section to AGENTS.md (lifesteal/healing ban)
- Add mana types overview to README.md and AGENTS.md
- All 44 tests pass, lint clean

src/components/game/tabs/SpireTab.tsx

@@ -183,9 +183,13 @@ export function SpireTab({ store }: SpireTabProps) {
                         <div className="flex gap-1 flex-wrap mt-1">
                           {spellDef.effects.map((eff, i) => (
                             <Badge key={i} variant="outline" className="text-xs py-0">
-                              {eff.type === 'lifesteal' && `🩸 ${Math.round(eff.value * 100)}%`}
                               {eff.type === 'burn' && `🔥 Burn`}
                               {eff.type === 'freeze' && `❄️ Freeze`}
+                              {eff.type === 'stun' && `⚡ Stun`}
+                              {eff.type === 'armor_pierce' && `🗡️ Pierce`}
+                              {eff.type === 'buff' && `⬆ Buff`}
+                              {eff.type === 'chain' && `⛓️ Chain`}
+                              {eff.type === 'aoe' && `💥 AOE`}
                             </Badge>
                           ))}
                         </div>