feat: Click CLI wrapper for cantaloupe export

- cantaloupe/ package with click CLI (python -m cantaloupe export)
- export command: --output, --headless/--visible, --scheduled, --email, --password
- configure command: saves credentials to ~/.cantaloupe.env (600 perms)
- cantaloupe/config.py: credential loading from env vars + env file
- Updated src/auth.py _get_credentials() to also check ~/.cantaloupe.env
- File size, row count (openpyxl), and elapsed time reporting
- 39 new CLI/config tests + 4 updated auth tests; 86/86 pass

src/auth.py

@@ -57,13 +57,36 @@ class AuthSession:
 
 
 def _get_credentials() -> tuple[str, str]:
-    """Read credentials from environment variables."""
+    """Read credentials from environment variables or ~/.cantaloupe.env."""
     email = os.environ.get("CANTALOUPE_EMAIL")
     password = os.environ.get("CANTALOUPE_PASSWORD")
+
+    # If env vars are set, use them
+    if email and password:
+        return email, password
+
+    # Fall back to ~/.cantaloupe.env
+    env_file = os.path.expanduser("~/.cantaloupe.env")
+    if os.path.exists(env_file):
+        for line in open(env_file).read().splitlines():
+            line = line.strip()
+            if not line or line.startswith("#") or "=" not in line:
+                continue
+            key, _, value = line.partition("=")
+            key = key.strip()
+            value = value.strip().strip('"').strip("'")
+            if key == "CANTALOUPE_EMAIL" and not email:
+                email = value
+            elif key == "CANTALOUPE_PASSWORD" and not password:
+                password = value
+
     if not email or not password:
         raise AuthenticationError(
             "Credentials not found. Set CANTALOUPE_EMAIL and CANTALOUPE_PASSWORD "
-            "environment variables."
+            "environment variables, or create ~/.cantaloupe.env with:\n"
+            "  CANTALOUPE_EMAIL=you@example.com\n"
+            "  CANTALOUPE_PASSWORD=your_password\n"
+            "Or run: python -m cantaloupe configure"
         )
     return email, password