feat(enakgame): budget controller recommendations and analytics

EnakGame phase 9 of docs/tasks-enakgame.md (EG-901 to EG-903).

Budget Controller (EG-901, EG-902)
- GET /marketing/enakgame/budgets/:id/recommendation, GLOBAL budgets only: the
  multiplier (budget − realized) / (forecast − realized), within one step of 1,
  rounded down to two decimals, either way. Shows each game's new rules.
- POST .../recommendation/accept with the multiplier the admin saw: recomputed in the
  transaction, then one new ACTIVE version per game, the old one RETIRED, audited
  with source budget_controller and RECOMMENDATION_ACCEPTED on the budget.
- Migration 000112: base_config_id, multiplier and budget_id on
  game_reward_configs. Rules are always scaled from the admin's last version, so
  rounding does not compound and min/max are against what the admin set.
- Guardrails in game_budgets.thresholds: max_step_percent 10, min/max multiplier
  50-150%, cooldown_days 7 per organization. Provisional pending RFC §19.2 #4.
- RewardCalculator.Scale for the four reward types: amounts only, rounded down.

Analytics (EG-903)
- GET /marketing/enakgame/analytics/games and /analytics/economy over a range of
  Asia/Jakarta days (at most 366), from game_sessions and the wallet ledger.
- Migrations 000113 (game_sessions by organization and start) and 000114
  (wallet_transactions by organization and time, CONCURRENTLY).

The Postgres tests for accepting and analytics were not run: no test database here.
Migrations 000112-000114 have not been run anywhere.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

migrations/000113_index_game_sessions_org_started.down.sql

@@ -0,0 +1 @@
+DROP INDEX IF EXISTS idx_game_sessions_org_started;