fix: restore complete _SENSITIVE_FIELDS_EXACT list from original commit

Was missing 13 entries (credentials, token, access_token, refresh_token,
auth_token, session_token, client_secret, auth_client_secret,
azure_client_secret, service_account_json, aws_session_token, credential,
secret). Now matches the original list from commit 46b4b2e9.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

mem0/memory/main.py

@@ -70,6 +70,19 @@ _SENSITIVE_FIELDS_EXACT = frozenset({
     "private_key",
     "access_key",
     "password",
+    "credentials",
+    "credential",
+    "secret",
+    "token",
+    "access_token",
+    "refresh_token",
+    "auth_token",
+    "session_token",
+    "client_secret",
+    "auth_client_secret",
+    "azure_client_secret",
+    "service_account_json",
+    "aws_session_token",
 })
 
 # Suffixes that indicate a field likely holds a secret value.