Initial scaffold: Nakama backend, Godot client, content schema

Sets up the Step 1 (Project Foundation) and Step 2 (Content Schemas) scaffold
from the implementation sequence. Includes Docker Compose stack, Nakama
TypeScript module stubs, PostgreSQL migration, Godot 4 project shell with
scene stubs and NakamaClient singleton, YAML content schemas for all entity
types, and example data for 3 characters, 2 jobs, and all 7 core resources.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

nakama/modules/auth.ts

@@ -0,0 +1,56 @@
+// auth.ts — account lifecycle hooks
+//
+// Seeds a new player account with starter resources and one guaranteed
+// starter character pull. Everything here must be idempotent: if called
+// more than once on the same account (e.g. after a reconnect), it must
+// not duplicate grants.
+
+const STARTER_RESOURCES: Record<string, number> = {
+  gold: 500,
+  wood: 200,
+  stone: 100,
+  knowledge: 50,
+  experience: 0,
+  mana: 30,
+  diamond: 100, // starter diamonds — enough to feel the pull system
+};
+
+const STORAGE_KEY_SEEDED = "account_seeded";
+
+export function afterAuthenticateDevice(
+  ctx: nkruntime.Context,
+  logger: nkruntime.Logger,
+  nk: nkruntime.Nakama,
+  out: nkruntime.Session,
+  _in: nkruntime.AuthenticateDeviceRequest
+): void {
+  const userId = ctx.userId;
+
+  // Guard: only seed once
+  const existing = nk.storageRead([
+    { collection: "player", key: STORAGE_KEY_SEEDED, userId },
+  ]);
+  if (existing.length > 0) return;
+
+  logger.info(`Seeding new account: ${userId}`);
+
+  // Grant starter wallet balances
+  const walletChangeset: { [key: string]: number } = STARTER_RESOURCES;
+  nk.walletUpdate(userId, walletChangeset, { source: "new_account_seed" });
+
+  // Mark account as seeded so this block never runs again
+  nk.storageWrite([
+    {
+      collection: "player",
+      key: STORAGE_KEY_SEEDED,
+      userId,
+      value: { seeded_at: Date.now() },
+      permissionRead: 1,
+      permissionWrite: 0,
+    },
+  ]);
+
+  // TODO PR 3: write player profile object (display name, server, region)
+  // TODO PR 4: create ledger entry for seed grant
+  // TODO PR 5: trigger one free starter banner pull
+}