Adds _HYBRID_BERT_LABEL_MAP to translate the 7-class output vocabulary of
krishnas4415/log-anomaly-detection-models (Hybrid-BERT, MIT) to Turnstone
SeverityLabel. _map_label now checks the Hybrid-BERT map before the standard
map so either model family works via TURNSTONE_CLASSIFIER_MODEL without any
additional code path.
Mapping (confirmed from model config.json):
normal → INFO
security_anomaly → ERROR
system_failure → CRITICAL
performance_issue → WARN
network_anomaly → WARN
config_error → ERROR
hardware_issue → CRITICAL
Keyword-based CRITICAL promotion and low-confidence DEBUG demotion apply on
top of the base mapping (same rules as the standard vocabulary).
11 new tests covering all 7 Hybrid-BERT labels, case-insensitivity, and
regression on standard-vocabulary labels. 372 tests passing total.
Note: custom loading code for the non-standard .pt checkpoint format is
explicitly out of scope — evaluate better-packaged HF alternatives first
(see #41 for candidate list).
Closes: #41