feat(api,ui): showcase-completion E4 — run-config phase controls (#410)

alembic/versions/b7c1d9e3f204_add_showcase_workspace_run_config.py

@@ -0,0 +1,41 @@
+"""add showcase_workspace run_config column
+
+Revision ID: b7c1d9e3f204
+Revises: d45cf40dfe47
+Create Date: 2026-06-13 12:00:00.000000
+
+E4 of the showcase-completion initiative (umbrella #406, epic #410). Adds a
+single nullable JSONB ``run_config`` column to ``showcase_workspace`` -- a
+REPLAY-INPUT column in the same class as ``seed`` / ``scenario`` / ``reset`` /
+``skip_seed`` (NOT an E1 story slot; see docs/_base/DOMAIN_MODEL.md D1). It
+records the start-frame model set + backtest config a ``preservation="keep"``
+run was launched with, so Load/Replay can reproduce it verbatim. NULL when the
+run used default config. No index (the read path is by ``workspace_id``; the
+column is a display/replay payload). Forward-only.
+"""
+
+from collections.abc import Sequence
+
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision: str = "b7c1d9e3f204"
+down_revision: str | None = "d45cf40dfe47"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+
+def upgrade() -> None:
+    """Add the nullable ``run_config`` JSONB column."""
+    op.add_column(
+        "showcase_workspace",
+        sa.Column("run_config", postgresql.JSONB(astext_type=sa.Text()), nullable=True),
+    )
+
+
+def downgrade() -> None:
+    """Drop the ``run_config`` column."""
+    op.drop_column("showcase_workspace", "run_config")

app/features/demo/models.py

@@ -63,6 +63,7 @@ class ShowcaseWorkspace(TimestampMixin, Base):
         date_end: Seeded data window end; NULL when unknown.
         created_objects: Soft-reference ids of everything the run created (JSONB).
         result_summary: Winner / WAPE / wall-clock display payload (JSONB).
+        run_config: Replay-input run config -- model set + backtest knobs (E4 #410); NULL on defaults.
         archived: Operator curation flag -- archived rows still list in E1.
         pinned: Operator curation flag -- no behavioral semantics in E1.
         notes: Free-text operator annotation (capped at the Pydantic boundary).
@@ -102,6 +103,14 @@ class ShowcaseWorkspace(TimestampMixin, Base):
     )
     # winner_model_type / winner_wape / wall_clock_s -- display payload.
     result_summary: Mapped[dict[str, Any] | None] = mapped_column(JSONB, nullable=True)
+    # E4 (#410) -- replay-input run config (NOT an E1 story slot; see
+    # DOMAIN_MODEL.md D1). Shape: {"train_model_types": [...], "backtest": {...}}
+    # via model_dump(mode="json"); NULL when the run used default config.
+    # Written by create_workspace at insert time (a replay input known before
+    # step 1, like seed/scenario); consumed by Load/Replay. config_schema_version
+    # is deliberately NOT bumped -- it versions the STORY-SLOT schema; run_config
+    # presence is NULL-detectable and carries its own documented shape.
+    run_config: Mapped[dict[str, Any] | None] = mapped_column(JSONB, nullable=True)
 
     # ── E1 (#407) — lifecycle metadata ────────────────────────────────────
     # Orthogonal to ``status`` (which the pipeline owns): archive/pin are