Migrate data pipeline from SQLite to PostgreSQL + Docker setup

- Add db.py PostgreSQL abstraction layer (connection, upsert, table mgmt)
- Replace sqlite3 with psycopg2 in: live_candle_fetcher, resampler,
  data_fetcher, fetch_history, import_csv, indicators, base_strategy
- Sanitize table names (colons -> underscores) for PostgreSQL compat
- Replace INSERT OR REPLACE with ON CONFLICT upserts
- Replace pandas to_sql() with batch upsert_candles()
- Add scripts: resampler_loop, gap_detector, backup_runner, cron_scheduler
- Add migrate_sqlite_to_pg.py for one-time data migration
- Add Dockerfile, docker-compose.yml, supervisord.conf
- Add postgres/postgresql.conf tuned for 4GB RAM (Synology DS1513+)
- Add .dockerignore, .env.docker.example, secrets template
- Update requirements.txt (psycopg2-binary), .gitignore
- Add MIGRATION_PLAN.md with full plan and todo list

import_csv.py

@@ -2,7 +2,7 @@ import argparse
 import logging
 import os
 import sys
-import sqlite3
+import db
 import pandas as pd
 from datetime import datetime
 
@@ -24,8 +24,8 @@ class CsvImporter:
         self.csv_path = csv_path
         self.coin = coin
         # --- FIX: Corrected the f-string syntax for the table name ---
-        self.table_name = f"{self.coin}_1m"
-        self.db_path = os.path.join("_data", "market_data.db")
+        self.table_name = db.sanitize_table_name(self.coin, "1m")
+        self.db_path = os.environ.get("PG_CONN_STR", "postgresql://hyper:hyper@localhost:5432/hyper")
         self.column_mapping = {
             'Open time': 'datetime_utc',
             'Open': 'open',
@@ -40,9 +40,8 @@ class CsvImporter:
         """Orchestrates the entire import and verification process."""
         logging.info(f"Starting import process for '{self.coin}' from '{self.csv_path}'...")
 
-        with sqlite3.connect(self.db_path) as conn:
-            conn.execute("PRAGMA journal_mode=WAL;")
-            
+        conn = db.get_connection()
+        try:
             # 1. Get the current state of the database
             db_oldest, db_newest, initial_row_count = self._get_db_state(conn)
 
@@ -58,6 +57,8 @@ class CsvImporter:
 
             # 4. Summarize and verify the import
             self._summarize_import(initial_row_count, len(new_data_df), conn)
+        finally:
+            conn.close()
 
     def _get_db_state(self, conn) -> (datetime, datetime, int):
         """Gets the oldest and newest timestamps and total row count from the DB table."""
@@ -104,9 +105,10 @@ class CsvImporter:
         return df_filtered
 
     def _append_to_db(self, df: pd.DataFrame, conn):
-        """Appends the DataFrame to the SQLite table."""
+        """Appends the DataFrame to the database."""
         logging.info(f"Appending {len(df):,} new rows to the database...")
-        df.to_sql(self.table_name, conn, if_exists='append', index=False)
+        records = list(df.itertuples(index=False, name=None))
+        db.upsert_candles(conn, self.table_name, records)
         logging.info("Append operation complete.")
 
     def _summarize_import(self, initial_count: int, added_count: int, conn):