Add MySQL contacts table + mysql backend for vm_contacts

- CREATE TABLE contacts (number_e164 UNIQUE, name, email) in asterisk DB
- new lookup_mysql() backend, registered as first in _BACKENDS
- vm_import_contacts.py: import VCF into MySQL (527 added)
- contacts.conf: backends=mysql,file
- live: 16 of 130 messages resolved via MySQL contacts

src/vm_contacts.py

@@ -3,6 +3,7 @@
 Caller-ID -> contact name resolution for Asterisk voicemail notifications.
 
 Backends (tried in the order given by contacts.conf 'backends='):
+  mysql   - MySQL contacts table on the asterisk DB (primary, fast, offline).
   file    - local vCard (.vcf) or CSV export; no auth, offline, fast.
   google  - Google People API via the Hermes OAuth token.
   carddav - generic CardDAV with username + app password.
@@ -21,6 +22,7 @@ import configparser
 import json
 import os
 import re
+import sys
 import time
 import urllib.error
 import urllib.parse
@@ -311,6 +313,41 @@ def lookup_google(cfg, num_digits, n, log):
     return None
 
 
+# ----------------------------------------------------------- mysql backend
+def lookup_mysql(cfg, num_digits, n, log):
+    """Look up a contact in the asterisk MySQL DB contacts table.
+
+    Uses vm_store.connect() so it shares the same asterisk DB config and
+    PyMySQL dependency already required by the portal.  If the table does
+    not not exist yet, run vm_import_contacts.py to create and populate it.
+    """
+    try:
+        sys_path = os.path.dirname(os.path.abspath(__file__))
+        if sys_path not in sys.path:
+            sys.path.insert(0, sys_path)
+        import vm_store  # noqa: E402  (local import to avoid hard dep at import time)
+    except Exception as e:
+        log("contacts mysql backend: vm_store unavailable (%s)" % e)
+        return None
+
+    num = extract_number(num_digits)
+    if not num:
+        return None
+    try:
+        con = vm_store.connect()
+        row = con.execute(
+            "SELECT name, email FROM contacts "
+            "WHERE number_e164 = ? AND name IS NOT NULL AND name != '' "
+            "ORDER BY id LIMIT 1",
+            (num,)).fetchone()
+        con.close()
+        if row:
+            return (row["name"], row.get("email") or None)
+    except Exception as e:
+        log("contacts mysql backend error: %s" % e)
+    return None
+
+
 # ---------------------------------------------------------- carddav backend
 def lookup_carddav(cfg, num_digits, n, log):
     import ssl
@@ -356,7 +393,7 @@ def lookup_carddav(cfg, num_digits, n, log):
 
 
 # ---------------------------------------------------------------- entrypoint
-_BACKENDS = {"file": lookup_file, "google": lookup_google, "carddav": lookup_carddav}
+_BACKENDS = {"mysql": lookup_mysql, "file": lookup_file, "google": lookup_google, "carddav": lookup_carddav}
 
 
 def resolve(caller_id, log=print):