feat: flexible cookie auth (substack.sid and/or connect.sid), markdown notes, retries, note deletion

.env.example

@@ -1,15 +1,22 @@
 # Environment variables for running E2E tests
 # Copy this file to .env and fill in your actual values
+#
+# Get cookie values from your browser: DevTools -> Application -> Cookies
+# -> https://substack.com -> copy the cookie value.
+# Provide at least one of SUBSTACK_SID / CONNECT_SID (some accounts only
+# have one of the two).
 
-# Required: Your Substack API key (obtained from your Substack account)
-# This is used for authentication in E2E tests
-SUBSTACK_API_KEY=your-api-key-here
+# Value of the "substack.sid" cookie
+SUBSTACK_SID=
 
-# Optional: The hostname of your Substack publication
-# If not set, defaults to 'substack.com'
+# Value of the "connect.sid" cookie
+CONNECT_SID=
+
+# The hostname of your Substack publication
 # Example: yoursite.substack.com
 SUBSTACK_HOSTNAME=
 
-# Alternative environment variable names (for flexibility)
-# E2E_API_KEY=your-api-key-here
-# E2E_HOSTNAME=yoursite.substack.com
+# Legacy names (substack-api compatibility): treated as SUBSTACK_SID
+# SUBSTACK_API_KEY=
+# E2E_API_KEY=
+# E2E_HOSTNAME=