Add integration tests for execution persistence, metrics, and opportunity writing

- Implemented integration tests for the execution writer to ensure trade orders and PnL are persisted correctly.
- Created integration tests for the metrics calculator to summarize execution data accurately.
- Added integration tests for the opportunity writer to verify event persistence.
- Established PostgreSQL schema validation tests to ensure all expected tables, columns, and constraints exist.
- Removed outdated unit tests that relied on DuckDB and replaced them with tests using PgStore.

README.md

@@ -6,7 +6,7 @@ Current stack:
 
 - Python 3.12+
 - FastAPI + HTMX/Jinja2
-- DuckDB for dev/test/prod
+- PostgreSQL for all environments (via asyncpg)
 - Native Kraken WebSocket planned for market-data hot path
 - Gitea Actions + Gitea container registry
 
@@ -22,7 +22,7 @@ Bootstrap complete for foundation layer:
 - typed settings and env loading
 - structured logging
 - encrypted secret helpers
-- DuckDB connection + base schema
+- PostgreSQL connection + full schema migration
 - FastAPI app with health endpoint
 - Gitea Actions CI scaffold
 - Docker / docker-compose scaffold
@@ -152,7 +152,11 @@ APP_HOST=0.0.0.0
 APP_PORT=9090
 LOG_LEVEL=INFO
 LOG_JSON=true
-DUCKDB_PATH=./data/arbitrade.duckdb
+PG_HOST=192.168.88.35
+PG_PORT=5432
+PG_DATABASE=arbitrade
+PG_USER=arbitrade
+PG_PASSWORD=arbitrade
 FERNET_KEY=
 KRAKEN_API_KEY=
 KRAKEN_API_SECRET=
@@ -182,15 +186,19 @@ Health endpoints:
 
 ## Database
 
-DuckDB used everywhere: local dev, tests, production.
+PostgreSQL used everywhere: local dev, tests, production.
 
-Default database file:
+Default connection:
 
 ```text
-./data/arbitrade.duckdb
+PG_HOST=192.168.88.35
+PG_PORT=5432
+PG_DATABASE=arbitrade
+PG_USER=arbitrade
+PG_PASSWORD=arbitrade
 ```
 
-Schema bootstrap runs automatically on app startup.
+Schema bootstrap runs automatically on app startup via `PgStore.migrate()`.
 
 Current tables:
 
@@ -220,7 +228,7 @@ DELETE FROM audit_events
 WHERE occurred_at < NOW() - INTERVAL 30 DAY;
 ```
 
-- Back up archive files and the main DuckDB file together.
+- Back up archive files and the PostgreSQL database together.
 - For production, run archive + backup as scheduled maintenance (cron/task scheduler).
 
 ## Quality Checks
@@ -342,7 +350,7 @@ Add a persistent volume in Coolify:
 
 - Mount Path: `/app/data`
 
-This preserves DuckDB and other runtime artifacts across restarts/redeploys.
+This preserves PostgreSQL data and other runtime artifacts across restarts/redeploys.
 
 ### 5) Configure environment variables
 
@@ -351,7 +359,11 @@ Add runtime environment variables in Coolify (UI: Environment Variables):
 - `APP_ENV=prod`
 - `APP_HOST=0.0.0.0`
 - `APP_PORT=9090`
-- `DUCKDB_PATH=/app/data/arbitrade.duckdb`
+- `PG_HOST=postgres`
+  `PG_PORT=5432`
+  `PG_DATABASE=arbitrade`
+  `PG_USER=arbitrade`
+  `PG_PASSWORD=arbitrade`
 - `LOG_LEVEL=INFO`
 - `LOG_JSON=true`
 - `KRAKEN_API_KEY=...`