Add Strike ticker poller, Docker .env config, and Frankfurter retry logic

- Poll Strike API every 10s, store all rates as JSONB in strike_price table
- Move Docker env vars to .env file, use shared network for cross-project communication
- Add startup retry (5x 5s) for Frankfurter poller to handle container race condition

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

resources/migrations/20260306000000-create-strike-price.up.sql

@@ -0,0 +1,5 @@
+CREATE TABLE strike_price (
+  id          BIGSERIAL PRIMARY KEY,
+  rates       JSONB       NOT NULL,
+  recorded_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);