feat: add OMEN attack as menu option 16

Add OMEN (Ordered Markov ENumerator) as a probability-ordered password
candidate generator. Trains n-gram models on leaked passwords via
createNG, then pipes candidates from enumNG into hashcat.

Also fix a pre-existing bug where ensure_binary() used quit(1) instead
of sys.exit(1) - quit() closes stdin before raising SystemExit, which
caused "ValueError: I/O operation on closed file" when any optional
binary check failed and the program continued to use input().

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

config.json.example

@@ -24,5 +24,7 @@
   "hashview_api_key": "",
   "hashmob_api_key": "",
   "ollamaModel": "mistral",
-  "ollamaNumCtx": 2048
+  "ollamaNumCtx": 2048,
+  "omenTrainingList": "rockyou.txt",
+  "omenMaxCandidates": 1000000
 }