Revert 253c922: restore the PM/RBAC work to the integration

Reverting the production revert so the pm branch can merge cleanly on
top of the restored RBAC base. Conflicts against newer integration work
resolved by combining:
- App.tsx: v7's bot-draft wizard bypass + login returnUrl kept alongside
  the supervisor gating (no-project block screen, panel scoping)
- LoginPage: returnUrl navigation kept, supervisor routing added
- migration.sql: bot_drafts table kept, unified-projects ALTERs restored

backend/app/routers/schedule_steps.py

@@ -3,6 +3,7 @@ from fastapi import APIRouter, Depends, Query
 from sqlalchemy import func, select
 from sqlalchemy.ext.asyncio import AsyncSession
 
+from app.auth import require_role
 from app.db.engine import get_db
 from app.models.procurement import Termsheet, TermsheetScheduleStep
 from app.schemas.procurement import ScheduleStepCreate, ScheduleStepUpdate
@@ -15,6 +16,7 @@ router = APIRouter(
     prefix="/quotes/{quote_id}/termsheets/{termsheet_id}/schedule-steps",
     tags=["schedule-steps"],
 )
+_procurement_writer = require_role("admin", "procurement_manager")
 
 
 async def _termsheet_or_404(db: AsyncSession, quote_id, termsheet_id) -> Termsheet:
@@ -57,7 +59,11 @@ async def list_schedule_steps(
 
 @router.post("", status_code=201)
 async def create_schedule_step(
-    quote_id, termsheet_id, payload: ScheduleStepCreate, db: AsyncSession = Depends(get_db)
+    quote_id,
+    termsheet_id,
+    payload: ScheduleStepCreate,
+    db: AsyncSession = Depends(get_db),
+    _auth=Depends(_procurement_writer),
 ):
     ts = await _termsheet_or_404(db, quote_id, termsheet_id)
     step_no = payload.step_no
@@ -84,7 +90,12 @@ async def create_schedule_step(
 
 @router.patch("/{step_id}")
 async def update_schedule_step(
-    quote_id, termsheet_id, step_id, payload: ScheduleStepUpdate, db: AsyncSession = Depends(get_db)
+    quote_id,
+    termsheet_id,
+    step_id,
+    payload: ScheduleStepUpdate,
+    db: AsyncSession = Depends(get_db),
+    _auth=Depends(_procurement_writer),
 ):
     step = await _step_or_404(db, termsheet_id, step_id)
     if payload.step_no is not None and payload.step_no != step.step_no:
@@ -109,7 +120,13 @@ async def update_schedule_step(
 
 
 @router.delete("/{step_id}")
-async def delete_schedule_step(quote_id, termsheet_id, step_id, db: AsyncSession = Depends(get_db)):
+async def delete_schedule_step(
+    quote_id,
+    termsheet_id,
+    step_id,
+    db: AsyncSession = Depends(get_db),
+    _auth=Depends(_procurement_writer),
+):
     step = await _step_or_404(db, termsheet_id, step_id)
     count = await db.scalar(
         select(func.count()).select_from(TermsheetScheduleStep).where(