[yashaskn8]

Verified base

• Based on main 358c48cad5301dc7dbd68f7f7b4fcecb530f512e.
• V5 already has a local SHA-pinned checkpoint loader and an opt-in Django reranker; private weights are intentionally not stored in Git.

Change

• Make python manage.py verify_v5_reranker run the same actual rerank_candidates path as production, including raw logits, instead of a separate default-activation model.predict() probe.
• Treat disabled model, unavailable checkpoint, legacy fallback, and non-finite scoring as smoke-verification failures.
• Add synthetic tests for raw-logit identity activation and failure handling; document scope and deployment instructions.

Important limitations

• Not a production promotion. The actual 2.27 GB V5 best_model checkpoint and its running environment were not accessible, and an independent holdout is not established.
• No model artifacts, personal/company text, secrets, or customer data were committed.
• Baseline MiniLM remains default, and V5 is opt-in.
• Real-weight path: offline installer -> SERVY_RERANKER_*=... -> smoke command -> SERVY_TEST_REAL_V5=1 end-to-end check -> independent quality/latency/citation/safety evaluation.
• This PR does not claim the trained model is installed or deployed.

Verification

• Awaiting GitHub MySQL backend tests, synthetic V5 tests, frontend lint/build. No real-weight test is runnable in CI absent the private checkpoint.

October 29 follow-up: required-model startup gate

• Added opt-in SERVY_RERANKER_REQUIRED=1 with a synchronous Django CoreConfig.ready() check. In this mode the application refuses to start unless enabled, SHA-pinned V5 inference produces a finite score through the real reranker. Required-mode request-time inference failures also propagate instead of falling back to baseline, including through retrieve(). Default/off behavior stays unchanged.
• Added eight synthetic regression tests for disabled/wrong-digest/missing-checkpoint conditions, successful raw-logit scoring, application startup failure, and subsequent request-time model failures; updated the environment example and V5 setup guide.
• This is not proof of a loaded private checkpoint, production deployment, independent accuracy, or a successful real-weight HTTP request. SERVY_TEST_REAL_V5=1 remains an operator-run verification gate after approved weights are installed.
• GitHub Actions for new head must be reviewed separately from prior CI runs.