feat: flat spell frontmatter, full source-book titles, drop circle

Parser reads human-friendly flat keys (range, targets, castingTime, overcast
list, threshold/successes, ...) and expands them to SpellData; fixes
[object Object] range, empty targets/casting time and blank overcast rows.
SOURCE_BOOKS ids now match vault slugs and show full book titles.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

templates/actor/npc.hbs

@@ -206,8 +206,7 @@
         <div class="row spell-row">
             <span class="badge mode mode-{{sp.system.castingMode}}"
                 title="{{localize (concat 'HBM.spell.castingMode.' sp.system.castingMode)}}">{{sp.system.castingMode}}</span>
-            <span class="spell-name"><strong>{{sp.name}}</strong>{{#if sp.system.circle}}
-                <small>K{{sp.system.circle}}</small>{{/if}}</span>
+            <span class="spell-name"><strong>{{sp.name}}</strong></span>
             <button type="button" data-action="castSpell" data-item-id="{{sp.id}}"
                 title="{{localize 'HBM.spell.cast'}}">✦ {{localize 'HBM.spell.cast'}}</button>
             <button type="button" data-action="editItem" data-item-id="{{sp.id}}"