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/progression.ts

@@ -0,0 +1,68 @@
+// progression.ts — character level, ascension, and skill upgrade
+//
+// All upgrade cost validation is server-side. Costs come from content data
+// (content/data/characters/), not hardcoded constants, so they can be tuned
+// without code changes.
+//
+// Progression layers (per spec):
+//   1. Character level (capped per ascension tier)
+//   2. Ascension / limit break (unlocks higher level cap, costs materials)
+//   3. Skill upgrades (costs knowledge + gold)
+//   4. Equipment (deferred beyond PoC)
+//   5. Bond / familiarity (tracked; mechanical outputs deferred)
+//   6. Assignment mastery (tracked in village module)
+
+export function rpcLevelUp(
+  ctx: nkruntime.Context,
+  logger: nkruntime.Logger,
+  nk: nkruntime.Nakama,
+  payload: string
+): string {
+  // TODO PR 6: validate level-up cost, deduct resources, write new level
+  const req = JSON.parse(payload || "{}");
+  logger.info(`progression/level_up stub: char=${req.character_id} user=${ctx.userId}`);
+
+  return JSON.stringify({
+    ok: false,
+    error: "not_implemented",
+    message: "Level-up is stubbed. Implement in PR 6.",
+    character_id: req.character_id,
+  });
+}
+
+export function rpcAscend(
+  ctx: nkruntime.Context,
+  logger: nkruntime.Logger,
+  nk: nkruntime.Nakama,
+  payload: string
+): string {
+  // TODO PR 6: validate ascension materials, raise tier, uncap level
+  const req = JSON.parse(payload || "{}");
+  logger.info(`progression/ascend stub: char=${req.character_id} user=${ctx.userId}`);
+
+  return JSON.stringify({
+    ok: false,
+    error: "not_implemented",
+    message: "Ascension is stubbed. Implement in PR 6.",
+    character_id: req.character_id,
+  });
+}
+
+export function rpcUpgradeSkill(
+  ctx: nkruntime.Context,
+  logger: nkruntime.Logger,
+  nk: nkruntime.Nakama,
+  payload: string
+): string {
+  // TODO PR 6: validate skill upgrade cost, apply upgrade
+  const req = JSON.parse(payload || "{}");
+  logger.info(`progression/upgrade_skill stub: char=${req.character_id} skill=${req.skill_id} user=${ctx.userId}`);
+
+  return JSON.stringify({
+    ok: false,
+    error: "not_implemented",
+    message: "Skill upgrade is stubbed. Implement in PR 6.",
+    character_id: req.character_id,
+    skill_id: req.skill_id,
+  });
+}