feat(forecast): add feature frame v2

PR-BODY-DRAFT.md

@@ -0,0 +1,147 @@
+# feat(forecast): add feature frame v2
+
+Tracking issue: **#299** (under Forecast Intelligence roadmap epic **#295**).
+PRP: `PRPs/PRP-35-forecast-intelligence-A-feature-frame-v2.md`.
+
+## Summary
+
+Lands the **V2 feature-frame contract** as an **additive, opt-in** surface
+alongside the frozen V1 contract:
+
+- **Shared layer** — V2 column manifest (38 default / 53 max columns across 11
+  `FeatureGroup`s), `V2HistoricalSidecar` / `V2FutureSidecar` data carriers,
+  and `build_historical_feature_rows_v2` / `build_future_feature_rows_v2`
+  pure row builders. `app/shared/feature_frames/` stays leaf-level.
+- **Training path** — `POST /forecasting/train` accepts optional
+  `feature_frame_version: int = 1` and `feature_groups: list[str] | None = None`.
+  V2 bundles persist `feature_frame_version`, `feature_columns`,
+  `feature_groups`, `feature_safety_classes`, and `feature_pinned_constants`
+  in bundle metadata.
+- **Scenarios path** — `POST /scenarios/simulate` reads `feature_frame_version`
+  from the loaded bundle metadata and dispatches V1 vs V2 future-frame
+  assembly transparently.
+- **LOAD-BEARING leakage specs** — three new specs land alongside the V1
+  spec; never to be weakened:
+  - `app/shared/feature_frames/tests/test_leakage_v2.py`
+  - `app/features/forecasting/tests/test_regression_features_v2_leakage.py`
+  - `app/features/scenarios/tests/test_future_frame_v2_leakage.py`
+
+## V1 compatibility (back-compat invariant)
+
+- Every V1 export keeps its current signature, return type, and behaviour.
+- The load-bearing V1 leakage spec
+  (`app/shared/feature_frames/tests/test_leakage.py`) and 22 sibling V1
+  contract tests remain green **without modification**.
+- V1 bundles trained before this PR load, predict, scenario-simulate, and
+  backtest unchanged.
+- `feature_frame_version=1` is the default everywhere; legacy bundles that
+  predate the metadata field are treated as V1 via
+  `bundle.metadata.get("feature_frame_version", 1)`.
+- `feature_frame_version` lives on `TrainRequest`, **not** on
+  `ModelConfigBase` — adding it to the config would mutate every existing V1
+  `config_hash()` and orphan registry rows / aliases. Persisted to bundle
+  metadata instead.
+
+## V2 opt-in behaviour
+
+- A `TrainRequest` with `feature_frame_version=2` (optionally `feature_groups=[…]`)
+  triggers the V2 path; otherwise V1 runs unchanged.
+- Validator gates:
+  - V1 + `feature_groups` supplied → 422.
+  - V2 + unknown `FeatureGroup` name → 422.
+- Default V2 groups: `TARGET_HISTORY`, `CALENDAR`, `ROLLING`, `TREND`,
+  `PRICE_PROMO`, `LIFECYCLE` (38 columns). Phase-2 sidecar groups
+  (`INVENTORY`, `REPLENISHMENT`, `RETURNS`, `EXOGENOUS_WEATHER`,
+  `EXOGENOUS_MACRO`) are off by default so the MVP stays green on smaller
+  seeded DBs (max 53 columns when all enabled).
+- Pinned V2 constants: `EXOGENOUS_LAGS_V2=(1,7,14,28,56,364)`,
+  `ROLLING_WINDOWS_V2=(7,28,90)`, `TREND_WINDOWS_V2=(30,90)`,
+  `HISTORY_TAIL_DAYS_V2=400`.
+
+## Validation
+
+All four mandatory gates green locally on `Python 3.12`:
+
+```
+✅ uv run ruff check .                       All checks passed
+✅ uv run ruff format --check .              327 files already formatted
+✅ uv run mypy app/                          0 PRP-35 errors (3 pre-existing xgboost noise on dev)
+✅ uv run pyright app/                       0 PRP-35 errors (8 pre-existing optional-extra noise on dev)
+✅ uv run pytest -m "not integration"        1480 passed, 12 skipped, 264 deselected
+```
+
+40 V2 leakage tests across 3 LOAD-BEARING files all green; 23 V1 contract /
+leakage tests byte-stable.
+
+The 3 mypy + 8 pyright pre-existing errors stem from optional `lightgbm` /
+`xgboost` extras and are unrelated to PRP-35; CI runs `--all-extras` and won't
+see them.
+
+## No Alembic migration
+
+V2 reads only existing tables (`inventory_snapshot_daily`,
+`replenishment_event`, `sales_returns`, `exogenous_signal`, `promotion`,
+`product`) and writes nothing to the DB. `alembic heads` unchanged at
+`c1d2e3f40512`.
+
+## Deferred: V2 backtesting dispatch — tracked in #299
+
+PRP-35 lands V2 **training + scenarios + shared builders**. **Backtesting V2
+dispatch is deferred** and explicitly tracked in the
+"Deferred follow-up: V2 backtesting dispatch" section of **#299**.
+
+PRP-35 Task 13 reads *"READ `feature_frame_version` from the fitted bundle
+BEFORE the fold loop"*, but
+`app/features/backtesting/service.py:_run_model_backtest` trains fresh per
+fold from `BacktestConfig.model_config_main` and **does not load a fitted
+bundle**. The correct opt-in surface is a request-time field on
+`BacktestConfig` itself — a re-design Task 13 did not spec.
+
+**This PR does NOT claim completion of PRP-35 Tasks 13 or 18.** V1
+backtesting is unchanged; a V2-trained bundle still trains and
+scenario-simulates correctly. Only `/backtesting/run` remains V1-only until
+the follow-up under #299 lands. Integration tests (PRP-35 Tasks 15 + 16) and
+the PHASE/3 + PHASE/4 doc edits (Task 21) are also deferred there.
+
+## qwen3 stash status
+
+The session's `stash@{0}` ("local qwen3 rag demo changes before prp-35",
+`app/features/rag/models.py` +7/-2) is **not applied, not popped, not
+dropped**. The decision on it (write a real
+`INITIAL-rag-embedding-provider-pluggability.md` doc vs. add to
+`.git/info/exclude`) is carryover work, untouched by this PR.
+
+## Files changed
+
+```
+ M app/features/forecasting/routes.py            (+2)
+ M app/features/forecasting/schemas.py           (+70)
+ M app/features/forecasting/service.py           (+318)
+ M app/features/scenarios/feature_frame.py       (+193)
+ M app/features/scenarios/service.py             (+25)
+ M app/shared/feature_frames/__init__.py         (+79)
+ M docs/optional-features/10-baseforecaster-feature-contract.md (+40)
+ A app/shared/feature_frames/contract_v2.py
+ A app/shared/feature_frames/rows_v2.py
+ A app/shared/feature_frames/sidecar.py
+ A app/shared/feature_frames/tests/test_contract_v2.py
+ A app/shared/feature_frames/tests/test_leakage_v2.py
+ A app/features/forecasting/v2_loaders.py
+ A app/features/forecasting/tests/test_regression_features_v2_leakage.py
+ A app/features/scenarios/tests/test_future_frame_v2_leakage.py
+ A examples/forecasting/feature_frame_v2_preview.py
+ A PR-BODY-DRAFT.md
+```
+
+## Test plan
+
+- [ ] CI green on all five gates (ruff / mypy / pyright / pytest / migration-check).
+- [ ] Verify `/forecasting/train` accepts `feature_frame_version=2` with default groups.
+- [ ] Verify `/forecasting/train` accepts `feature_frame_version=2` with opt-in
+      Phase-2 group (e.g. `INVENTORY`) on a seeded DB carrying inventory rows.
+- [ ] Verify `/scenarios/simulate` against a V2-trained bundle produces a
+      `model_exogenous` re-forecast (V2 future-frame assembly via bundle metadata).
+- [ ] Verify a V1 bundle trained before this PR still loads, predicts, and
+      scenario-simulates unchanged.
+- [ ] Verify `/backtesting/run` against a V2-trained bundle remains V1-only
+      (no V2 dispatch on the fold loop) — documented deferral above.

app/features/forecasting/routes.py

@@ -103,6 +103,8 @@ async def train_model(
             train_start_date=request.train_start_date,
             train_end_date=request.train_end_date,
             config=request.config,
+            feature_frame_version=request.feature_frame_version,
+            feature_groups=request.feature_groups,
         )
 
         logger.info(

app/features/forecasting/schemas.py

@@ -13,7 +13,9 @@
 from enum import Enum
 from typing import Literal
 
-from pydantic import BaseModel, ConfigDict, Field, field_validator
+from pydantic import BaseModel, ConfigDict, Field, field_validator, model_validator
+
+from app.shared.feature_frames import FeatureGroup
 
 # =============================================================================
 # Model Configuration Schemas
@@ -312,6 +314,30 @@ class TrainRequest(BaseModel):
         description="End date of training period (inclusive)",
     )
     config: ModelConfig
+    # PRP-35: opt-in to the V2 feature contract (richer, leakage-safe). V1
+    # remains the default and the back-compat path; V2 callers also set
+    # ``feature_groups`` to pick the enabled :class:`FeatureGroup` subset.
+    # NOTE: these fields live on ``TrainRequest``, NOT on ``ModelConfigBase`` —
+    # adding them to the config would mutate every existing ``config_hash()``
+    # value, orphaning every registry row and alias. The resolved version is
+    # persisted into bundle metadata instead.
+    feature_frame_version: int = Field(
+        default=1,
+        ge=1,
+        le=2,
+        description=(
+            "Feature contract version. 1 = V1 (default, 14 columns, back-compat); "
+            "2 = V2 (richer manifest, opt-in)."
+        ),
+    )
+    feature_groups: list[str] | None = Field(
+        default=None,
+        description=(
+            "V2 only: optional list of FeatureGroup names to enable "
+            "(None → DEFAULT_V2_GROUPS). MUST be None / omitted when "
+            "feature_frame_version=1 (422 otherwise)."
+        ),
+    )
 
     @field_validator("train_end_date")
     @classmethod
@@ -323,6 +349,24 @@ def validate_date_range(cls, v: date_type, info: object) -> date_type:
             raise ValueError("train_end_date must be after train_start_date")
         return v
 
+    @model_validator(mode="after")
+    def validate_feature_frame_version_and_groups(self) -> TrainRequest:
+        """Reject ``feature_groups`` when V1 and unknown group names when V2."""
+        if self.feature_frame_version == 1 and self.feature_groups is not None:
+            raise ValueError(
+                "feature_groups is only valid when feature_frame_version=2; "
+                "omit it for V1 training."
+            )
+        if self.feature_frame_version == 2 and self.feature_groups is not None:
+            valid_names = {g.value for g in FeatureGroup}
+            unknown = [name for name in self.feature_groups if name not in valid_names]
+            if unknown:
+                raise ValueError(
+                    f"Unknown FeatureGroup name(s): {unknown!r}. "
+                    f"Valid names: {sorted(valid_names)}."
+                )
+        return self
+
 
 class TrainResponse(BaseModel):
     """Response body for POST /forecasting/train.
@@ -503,3 +547,27 @@ class FeatureMetadataResponse(BaseModel):
             "know what the numbers mean."
         ),
     )
+    # PRP-35 — purely additive V2 metadata. ``feature_frame_version`` defaults
+    # to 1 for legacy bundles (``bundle.metadata.get("feature_frame_version", 1)``).
+    # ``feature_groups`` / ``feature_safety_classes`` are populated for V2
+    # bundles only and absent (None) for V1.
+    feature_frame_version: int = Field(
+        default=1,
+        ge=1,
+        le=2,
+        description="Feature contract version recorded in the bundle metadata.",
+    )
+    feature_groups: dict[str, list[str]] | None = Field(
+        default=None,
+        description=(
+            "V2 only: ``{group_name: [columns]}`` mapping from "
+            "``v2_feature_groups_dict``. None for V1 bundles."
+        ),
+    )
+    feature_safety_classes: dict[str, str] | None = Field(
+        default=None,
+        description=(
+            "V2 only: ``{column: safety.value}`` mapping from "
+            "``v2_feature_safety_classes``. None for V1 bundles."
+        ),
+    )