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-overview.hbs

@@ -0,0 +1,61 @@
+<section data-tab="overview" data-group="{{tab.group}}" class="tab {{tab.cssClass}}">
+
+  <fieldset class="currency-bar">
+    <legend>{{localize "OATHHAMMER.Label.Treasury"}}</legend>
+    <div class="flexrow">
+      <div class="currency-item">
+        <label>{{localize "OATHHAMMER.Currency.GP"}}</label>
+        <div class="currency-stepper">
+          <a data-action="adjustCurrency" data-field="system.currency.gold" data-delta="-1" class="qty-btn">−</a>
+          {{formInput systemFields.currency.fields.gold value=system.currency.gold name="system.currency.gold"}}
+          <a data-action="adjustCurrency" data-field="system.currency.gold" data-delta="1" class="qty-btn">+</a>
+        </div>
+      </div>
+      <div class="currency-item">
+        <label>{{localize "OATHHAMMER.Currency.SP"}}</label>
+        <div class="currency-stepper">
+          <a data-action="adjustCurrency" data-field="system.currency.silver" data-delta="-1" class="qty-btn">−</a>
+          {{formInput systemFields.currency.fields.silver value=system.currency.silver name="system.currency.silver"}}
+          <a data-action="adjustCurrency" data-field="system.currency.silver" data-delta="1" class="qty-btn">+</a>
+        </div>
+      </div>
+      <div class="currency-item">
+        <label>{{localize "OATHHAMMER.Currency.CP"}}</label>
+        <div class="currency-stepper">
+          <a data-action="adjustCurrency" data-field="system.currency.copper" data-delta="-1" class="qty-btn">−</a>
+          {{formInput systemFields.currency.fields.copper value=system.currency.copper name="system.currency.copper"}}
+          <a data-action="adjustCurrency" data-field="system.currency.copper" data-delta="1" class="qty-btn">+</a>
+        </div>
+      </div>
+    </div>
+  </fieldset>
+
+  <div class="settlement-overview-grid">
+    <fieldset>
+      <legend>{{localize "OATHHAMMER.Label.Garrison"}}</legend>
+      {{formInput systemFields.garrison value=system.garrison name="system.garrison" disabled=isPlayMode}}
+    </fieldset>
+
+    <fieldset>
+      <legend>{{localize "OATHHAMMER.Label.Founded"}}</legend>
+      {{formInput systemFields.founded value=system.founded name="system.founded" disabled=isPlayMode}}
+    </fieldset>
+
+    <fieldset class="tax-notes">
+      <legend>{{localize "OATHHAMMER.Label.TaxNotes"}}</legend>
+      {{formInput systemFields.taxNotes value=system.taxNotes name="system.taxNotes" disabled=isPlayMode}}
+    </fieldset>
+  </div>
+
+  <fieldset>
+    <legend>{{localize "OATHHAMMER.Label.Description"}}</legend>
+    {{#if isEditMode}}
+    <prose-mirror name="system.description" toggled="false" collaborate="false">
+      {{{system.description}}}
+    </prose-mirror>
+    {{else}}
+    <div class="editor-content">{{{enrichedDescription}}}</div>
+    {{/if}}
+  </fieldset>
+
+</section>