[api][econ] add levels, xp storage and basic game rewards

apps/econ/migrations/0012_progression.sql

@@ -0,0 +1,21 @@
+-- Player progression (level + XP), owned by the `econ` worker as the writer, but shared:
+-- `econ` pays XP out (game rewards) and `api` reads it back for
+-- `GET /api/players/v{1,2}/progression/…`, so the helpers live in @repo/domain rather than
+-- in either worker. Same split as `received_gift`.
+--
+-- One row per account, created on the first grant. A missing row means "nothing earned
+-- yet", which is the level-1/0-XP default the progression endpoints already served — so
+-- reads fall back to it instead of inserting on a GET.
+--
+-- `level` is stored rather than derived: the reference server levels a player up by
+-- subtracting the tier's RequiredXp from the running XP, using thresholds from a config we
+-- don't have (configv2.json's LevelProgressionMaps). Until those numbers exist XP
+-- accumulates and everyone stays level 1; the column is here so turning the curve on later
+-- is a write, not a migration. Kept in sync with PROGRESSION_SCHEMA_DDL in
+-- packages/domain/src/progression-db.ts.
+
+CREATE TABLE IF NOT EXISTS progression (
+  account_id INTEGER PRIMARY KEY,
+  level INTEGER NOT NULL DEFAULT 1,
+  xp INTEGER NOT NULL DEFAULT 0
+  );