feat: add Settlement actor type with Overview/Buildings/Inventory tabs

- New TypeDataModel: archetype, territory, renown, currency (gp/sp/cp),
  garrison, underSiege, isCapital, founded, taxNotes, description, notes
- 3-tab ApplicationV2 sheet with drag & drop for building/weapon/armor/equipment
- Currency steppers (+/−), building constructed toggle, qty controls
- LESS-based CSS (settlement-sheet.less) + base.less updated for shared styles
- Full i18n keys in lang/en.json (8 settlement archetypes)
- system.json: registered settlement actor type

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

templates/actor/settlement-buildings.hbs

@@ -0,0 +1,41 @@
+<section data-tab="buildings" data-group="{{tab.group}}" class="tab {{tab.cssClass}}">
+  <p class="settlement-hint">{{localize "OATHHAMMER.Settlement.BuildingHint"}}</p>
+
+  {{#if buildings.length}}
+  <ul class="item-list item-list--buildings">
+    <li class="item-list-header">
+      <span></span>
+      <span class="col-name">{{localize "OATHHAMMER.Label.Name"}}</span>
+      <span>{{localize "OATHHAMMER.Label.Built"}}</span>
+      <span>{{localize "OATHHAMMER.Label.TaxRevenue"}}</span>
+      <span>{{localize "OATHHAMMER.Label.Cost"}}</span>
+      <span></span>
+    </li>
+    {{#each buildings as |building|}}
+    <li class="item-entry {{#if building.system.constructed}}building-constructed{{/if}}" data-item-id="{{building.id}}" data-item-uuid="{{building.uuid}}">
+      <img src="{{building.img}}" class="item-img" />
+      <span class="item-name" data-tooltip="{{building.name}}">{{building.name}}</span>
+      <span class="item-constructed">
+        {{#unless ../isPlayMode}}
+        <a data-action="toggleConstructed" data-item-id="{{building.id}}" class="construct-toggle">
+          <i class="fa-{{#if building.system.constructed}}solid{{else}}regular{{/if}} fa-square-check"></i>
+        </a>
+        {{else}}
+        <i class="fa-{{#if building.system.constructed}}solid{{else}}regular{{/if}} fa-square-check"></i>
+        {{/unless}}
+      </span>
+      <span class="item-tax {{#unless building.system.constructed}}item-tax--inactive{{/unless}}">
+        {{#if building.system.taxRevenue}}{{building.system.taxRevenue}}{{else}}—{{/if}}
+      </span>
+      <span class="item-cost">{{building.system.cost}} gp</span>
+      <div class="item-actions">
+        <a data-action="edit" data-item-id="{{building.id}}" data-item-uuid="{{building.uuid}}"><i class="fa-solid fa-edit"></i></a>
+        {{#unless ../isPlayMode}}<a data-action="delete" data-item-id="{{building.id}}" data-item-uuid="{{building.uuid}}"><i class="fa-solid fa-trash"></i></a>{{/unless}}
+      </div>
+    </li>
+    {{/each}}
+  </ul>
+  {{else}}
+  <p class="no-items">{{localize "OATHHAMMER.Settlement.NoBuildings"}}</p>
+  {{/if}}
+</section>