fix(tools): migrate email credentials to keyring, remove hardcoded password

Email tools now use credential_store (keyring) as primary source
with env/.env as fallback. Removes plaintext password from email_check.py.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

tools/email_check.py

@@ -10,12 +10,20 @@ from email.header import decode_header
 import json
 import sys
 from datetime import datetime
+from pathlib import Path
+
+# Try keyring first
+sys.path.insert(0, str(Path(__file__).parent.parent))
+try:
+    from src.credential_store import get_secret
+except ImportError:
+    get_secret = lambda name: None
 
 # IMAP Configuration
-IMAP_SERVER = "mail.romfast.ro"
+IMAP_SERVER = get_secret("email_server") or "mail.romfast.ro"
 IMAP_PORT = 993
-IMAP_USER = "moltbot@romfast.ro"
-IMAP_PASS = "parola281234"
+IMAP_USER = get_secret("email_user") or "echo@romfast.ro"
+IMAP_PASS = get_secret("email_password") or ""
 
 def decode_mime_header(header):
     """Decode MIME encoded header"""