oracle: add fixed four-epoch final protocol

docs/easycom_oracle_information.md

@@ -71,17 +71,39 @@ Sessions 1--3.
 If preparation reports any transcript/target mismatch, stop and inspect it;
 the preparation command has no mismatch-tolerance option.
 
+## Locked four-epoch train-all protocol
+
+The final protocol fixes the training budget at four epochs, trains on all
+official EasyCom training sessions (Sessions 4--12), performs no development
+checkpoint selection, and evaluates Sessions 1--3 once:
+
+```bash
+CUDA_VISIBLE_DEVICES=0 bash run_easycom_oracle_information.sh final 0 1 2
+```
+
+The `final` stage enforces `EPOCHS=4` and exactly Sessions 4--12, clears the
+development-session list internally, and saves the last epoch. Its artifacts
+use separate `_train4_12_fixed4` checkpoint/result roots by default, so they
+cannot overwrite the historical Session-12 development screen. Override those
+roots only with `FINAL_CHECKPOINT_ROOT` and `FINAL_RESULT_ROOT`.
+
+mAP itself does not require threshold calibration. Nevertheless, the official
+test results must not be used to choose a variant, epoch, loss, fusion design,
+or any later hyperparameter. Run `final` only after those decisions are frozen;
+repeatedly inspecting Sessions 1--3 and modifying the method would contaminate
+the official test split.
+
 ## Follow-up
 
-If `per-person` is consistently better on Session 12, add seeds 1 and 2 using
-the already prepared sidecars:
+To reproduce the historical Session-12 development screen for seeds 1 and 2,
+use the already prepared sidecars:
 
 ```bash
 CUDA_VISIBLE_DEVICES=0 bash run_easycom_oracle_information.sh screen 1 2
 ```
 
-Only after freezing the method and event evaluator should selected variants be
-run once on Sessions 1--3:
+The older two-stage equivalent of final test inference is retained for
+reproducibility, but the locked protocol above is preferred for new final runs:
 
 ```bash
 VARIANTS="audio aggregate-visible per-person shuffled-id delayed" \