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>

less/base.less

@@ -36,7 +36,8 @@
 
 // Shared actor content base
 .oathhammer .character-content,
-.oathhammer .npc-content {
+.oathhammer .npc-content,
+.oathhammer .settlement-content {
   font-family: @font-body;       // Calibri — standard text per design_rules.md
   font-size: @font-size-base;
   color: @color-dark;

less/fvtt-oath-hammer.less

@@ -11,3 +11,4 @@
 @import "item-sheets";
 @import "rolls";
 @import "roll-dialog";
+@import "settlement-sheet";

less/settlement-sheet.less

@@ -0,0 +1,172 @@
+// ============================================================
+// SETTLEMENT SHEET
+// ============================================================
+
+.oathhammer .settlement-main {
+  padding: 0 0 8px;
+  border-bottom: 1px solid fade(@color-dark, 25%);
+  margin-bottom: 4px;
+}
+
+.oathhammer .settlement-header {
+  align-items: flex-start;
+  gap: 10px;
+}
+
+.oathhammer .settlement-header .actor-img {
+  width: 72px;
+  height: 72px;
+  object-fit: cover;
+  border: 2px solid fade(@color-dark, 40%);
+  border-radius: 4px;
+  cursor: pointer;
+  flex-shrink: 0;
+}
+
+.oathhammer .settlement-header-info {
+  flex: 1;
+  display: flex;
+  flex-direction: column;
+  gap: 6px;
+}
+
+.oathhammer .settlement-name-row {
+  align-items: center;
+  gap: 8px;
+}
+
+.oathhammer .settlement-archetype-badge {
+  font-size: @font-size-sm;
+  color: darken(@color-paper, 40%);
+  background: fade(@color-gold, 15%);
+  border: 1px solid fade(@color-gold, 40%);
+  border-radius: 3px;
+  padding: 1px 6px;
+  white-space: nowrap;
+}
+
+.oathhammer .settlement-stats {
+  gap: 8px;
+  flex-wrap: wrap;
+  align-items: flex-start;
+
+  .stat-item {
+    display: flex;
+    flex-direction: column;
+    gap: 2px;
+    min-width: 80px;
+
+    label {
+      font-size: 0.72rem;
+      color: @color-dark;
+      opacity: 0.8;
+      text-transform: uppercase;
+      letter-spacing: 0.03em;
+    }
+
+    input { padding: 2px 4px; }
+
+    &--flags {
+      display: flex;
+      flex-direction: row;
+      gap: 8px;
+      align-items: center;
+      flex-wrap: wrap;
+      min-width: unset;
+
+      label {
+        display: flex;
+        align-items: center;
+        gap: 4px;
+        font-size: @font-size-sm;
+        text-transform: none;
+        letter-spacing: 0;
+        cursor: pointer;
+      }
+    }
+  }
+}
+
+.oathhammer .settlement-badge {
+  font-size: 0.75rem;
+  font-weight: bold;
+  border-radius: 3px;
+  padding: 2px 7px;
+
+  &--capital {
+    background: fade(@color-gold, 20%);
+    border: 1px solid fade(@color-gold, 50%);
+    color: darken(@color-gold, 30%);
+  }
+
+  &--siege {
+    background: rgba(180, 40, 40, 0.12);
+    border: 1px solid rgba(180, 40, 40, 0.4);
+    color: #8a1a1a;
+  }
+}
+
+.oathhammer .settlement-content .tab {
+  padding: 8px 0;
+}
+
+// Overview grid: garrison | founded | tax notes
+.oathhammer .settlement-overview-grid {
+  display: grid;
+  grid-template-columns: 1fr 1fr 2fr;
+  gap: 8px;
+  margin-bottom: 8px;
+}
+
+.oathhammer .settlement-hint {
+  font-size: 0.78rem;
+  color: @color-dark;
+  opacity: 0.7;
+  margin: 0 0 8px;
+  font-style: italic;
+}
+
+// Buildings item list
+.oathhammer .item-list--buildings {
+  .item-list-header,
+  .item-entry {
+    display: grid;
+    grid-template-columns: 28px 1fr 3rem 5rem 4rem 3rem;
+    align-items: center;
+    gap: 4px;
+  }
+}
+
+.oathhammer .item-entry.building-constructed {
+  background: rgba(60, 140, 60, 0.08);
+
+  .item-name { font-weight: 600; }
+}
+
+.oathhammer .item-constructed {
+  text-align: center;
+  font-size: 1rem;
+  color: #3a7a3a;
+}
+
+.oathhammer .item-tax {
+  font-size: @font-size-sm;
+  color: darken(@color-olive, 10%);
+  text-align: center;
+
+  &--inactive { opacity: 0.4; }
+}
+
+.oathhammer .item-cost {
+  font-size: @font-size-sm;
+  color: darken(@color-gold, 20%);
+  text-align: right;
+}
+
+.oathhammer .construct-toggle {
+  color: #3a7a3a;
+  cursor: pointer;
+  font-size: 1rem;
+
+  &:hover { color: darken(#3a7a3a, 15%); }
+}