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>

oath-hammer.mjs

@@ -23,7 +23,8 @@ Hooks.once("init", function () {
   CONFIG.Combat.documentClass = OathHammerCombat
   CONFIG.Actor.dataModels = {
     character: models.OathHammerCharacter,
-    npc: models.OathHammerNPC
+    npc: models.OathHammerNPC,
+    settlement: models.OathHammerSettlement
   }
 
   CONFIG.Item.documentClass = documents.OathHammerItem
@@ -52,6 +53,11 @@ Hooks.once("init", function () {
     makeDefault: true,
     label: "OATHHAMMER.Sheet.NPC"
   })
+  foundry.documents.collections.Actors.registerSheet("fvtt-oath-hammer", applications.OathHammerSettlementSheet, {
+    types: ["settlement"],
+    makeDefault: true,
+    label: "OATHHAMMER.Sheet.Settlement"
+  })
 
   foundry.documents.collections.Items.unregisterSheet("core", foundry.appv1.sheets.ItemSheet)
   foundry.documents.collections.Items.registerSheet("fvtt-oath-hammer", applications.OathHammerWeaponSheet, { types: ["weapon"], makeDefault: true, label: "OATHHAMMER.Sheet.Weapon" })