fix: load .env from current working directory, not source file directory

The previous load_dotenv() searched for .env starting from the calling
file's directory (haiku/rag/cli.py), which fails when users run haiku-rag
from a different directory containing their .env file.

Changes:
- Move load_dotenv() before config imports (config reads env vars at import time)
- Use find_dotenv(usecwd=True) to search from current working directory

haiku_rag_slim/haiku/rag/cli.py

@@ -8,7 +8,11 @@ from pathlib import Path
 from typing import Any
 
 import typer
-from dotenv import load_dotenv
+from dotenv import find_dotenv, load_dotenv
+
+# Load environment variables from .env file for API keys and service URLs.
+# Env loading needs to be before config import; usecwd=True searches from cwd, not this .py file's location
+load_dotenv(find_dotenv(usecwd=True))
 
 from haiku.rag.app import HaikuRAGApp
 from haiku.rag.config import (
@@ -22,9 +26,6 @@ from haiku.rag.logging import configure_cli_logging
 from haiku.rag.store.exceptions import MigrationRequiredError
 from haiku.rag.utils import is_up_to_date
 
-# Load environment variables from .env file for API keys and service URLs
-load_dotenv()
-
 _cli = typer.Typer(
     context_settings={"help_option_names": ["-h", "--help"]}, no_args_is_help=True
 )