Documentation update

docs/data-fetcher.md

@@ -2,7 +2,7 @@
 
 ## Initial Goal
 
-Create a Python module/tool that fetches daily candlestick data from the IBKR API for a specific ticker and date range.
+Create a Python module/tool that fetches daily candlestick data from the Alpaca Market Data API for a specific ticker and date range.
 
 The intended example workflow is:
 
@@ -14,41 +14,40 @@ The intended example workflow is:
 
 ## Current Implementation
 
-The first implementation is intentionally small:
+The current implementation is intentionally small:
 
 - ticker passed as a required command line argument;
 - end date passed with `--end-date YYYYMMDD`, defaulting to yesterday;
 - end date can also be derived with `--end-date-from-parquet`;
 - duration passed with `--duration`, defaulting to `1 W`;
-- hard-coded IBKR Gateway target: `127.0.0.1:4002`;
-- uses the IBKR API through `ib_insync`;
-- prints fetched candles as CSV-like rows;
+- uses the Alpaca Market Data API through `alpaca-py`;
+- reads credentials from `--api-key` / `--secret-key`, `ALPACA_API_KEY` / `ALPACA_SECRET_KEY`, or `.env`;
 - writes candles to a symbol-named Parquet file;
 - appends to an existing symbol file and keeps one row per date.
 
 Run it with:
 
 ```sh
-mise exec -- uv run python src/trading_bot/data/fetch_ibkr_daily.py SPY
+mise exec -- uv run python src/trading_bot/data/fetch_alpaca_daily.py SPY
 ```
 
 To override the requested range:
 
 ```sh
-mise exec -- uv run python src/trading_bot/data/fetch_ibkr_daily.py SPY --end-date 20250605 --duration "1 M"
+mise exec -- uv run python src/trading_bot/data/fetch_alpaca_daily.py SPY --end-date 20250605 --duration "1 M"
 ```
 
 To fetch backward from the oldest date already stored in the symbol file:
 
 ```sh
-mise exec -- uv run python src/trading_bot/data/fetch_ibkr_daily.py SPY --end-date-from-parquet
+mise exec -- uv run python src/trading_bot/data/fetch_alpaca_daily.py SPY --end-date-from-parquet
 ```
 
 `--end-date` and `--end-date-from-parquet` cannot be used together. If the symbol Parquet file does not exist or has no rows, `--end-date-from-parquet` uses today's US/Eastern date.
 
-This expects a local IBKR Gateway session to be running and accepting API connections on `127.0.0.1:4002`.
+This expects Alpaca API credentials to be available via CLI arguments, environment variables, or `.env`.
 
-By default, output is written to `data/ibkr/daily/SPY.parquet`. Use `--output-dir` to choose another directory.
+By default, output is written to `data/alpaca/daily/SPY.parquet`. Use `--output-dir` to choose another directory.
 
 Manual test instructions are in [manual-test/README.md](manual-test/README.md).
 
@@ -78,5 +77,5 @@ Candidate output schema:
 Open decisions:
 
 - how to handle adjusted versus unadjusted prices;
-- how to handle missing sessions and IBKR pacing limits;
-- whether to use `ib_insync` long term or a lower-level IBKR client wrapper.
+- how to handle missing sessions, market holidays, and Alpaca API rate limits;
+- whether to add explicit feed selection, adjustment settings, or data entitlement checks.