Stage 10: persist efficiency profile as stage artifact

Stage 10 was previously implicit — the per-discipline override sliders in
Stage 11 fed straight into team-shape calculations without leaving an
audit trail. This adds:
- POST /opportunities/{id}/efficiency-profile — saves the active
  scenario / blanket pct / discipline overrides / tools applied / notes
  as a stage_artifact (type='efficiency_profile').
- GET /opportunities/{id}/efficiency-profile — returns the most recent.

The payload shape is loose by design ({scenario, blanket_pct,
discipline_overrides, tools_applied, notes}) so the Stage 11 UI can
evolve without a migration. The artifact is the audit trail; the live
calculation still runs on the query params passed to GET /team-shape.

Smoke-tested against opp #2.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

backend/app/api/opportunities.py

@@ -519,6 +519,51 @@ async def post_support_docs(opportunity_id: int, db: AsyncSession = Depends(get_
     return await _run_simple_agent(db, opportunity_id, run_support_docs, 13, "support_docs")
 
 
+@router.post("/{opportunity_id}/efficiency-profile")
+async def save_efficiency_profile(
+    opportunity_id: int,
+    payload: dict,
+    db: AsyncSession = Depends(get_db),
+):
+    """Stage 10 — persist the efficiency profile (scenario + per-discipline
+    overrides + tools applied + notes) as a stage_artifact so the
+    team-shape inputs are audited alongside the rest of the pipeline.
+
+    Payload is intentionally loose: {scenario, blanket_pct,
+    discipline_overrides: {discipline: pct}, tools_applied: [str], notes}.
+    """
+    opp = await _get_opp(db, opportunity_id)
+    artifact = StageArtifact(
+        opportunity_id=opp.id,
+        stage_number=10,
+        artifact_type="efficiency_profile",
+        content_json=payload,
+    )
+    db.add(artifact)
+    await db.commit()
+    await db.refresh(artifact)
+    return {"artifact_id": artifact.id, "saved_at": artifact.created_at, "content": payload}
+
+
+@router.get("/{opportunity_id}/efficiency-profile")
+async def get_efficiency_profile(opportunity_id: int, db: AsyncSession = Depends(get_db)):
+    await _get_opp(db, opportunity_id)
+    result = await db.execute(
+        select(StageArtifact)
+        .where(
+            StageArtifact.opportunity_id == opportunity_id,
+            StageArtifact.stage_number == 10,
+            StageArtifact.artifact_type == "efficiency_profile",
+        )
+        .order_by(StageArtifact.created_at.desc())
+        .limit(1)
+    )
+    artifact = result.scalar_one_or_none()
+    if artifact is None:
+        return None
+    return {"artifact_id": artifact.id, "saved_at": artifact.created_at, "content": artifact.content_json}
+
+
 @router.get("/{opportunity_id}/qualification", response_model=QualificationScorecardOut | None)
 async def get_qualification(opportunity_id: int, db: AsyncSession = Depends(get_db)):
     """Return the most recent qualification scorecard, or null if none saved yet."""