revert: restore production to the state before 730d0bd (PM/RBAC work moved to 'pm')

Their three commits (730d0bd, 5a9b543, 387edfb) reached production by push and
auto-deployed. 387edfb expects a users.username column that the live database does
not have, so POST /api/v1/auth/login was returning HTTP 500. Their schema changes
never applied either (projects still has only id, name, description, start_date,
pm_user_id, created_at), so nothing depends on the reverted code.

This commit sets the tree back to exactly a02b3ea — verified with git diff against
it — while keeping history linear: the work itself is preserved on 'pm' at 387edfb.

backend/app/routers/units.py

@@ -3,7 +3,6 @@ from fastapi import APIRouter, Depends, Query
 from sqlalchemy import func, or_, select
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from app.auth import require_role
 from app.db.engine import get_db
 from app.models.catalog import AttributeDefinition, Material, MaterialUnit, Unit
 from app.models.procurement import LineItem, LineItemSpec
@@ -12,7 +11,6 @@ from app.utils.errors import ConflictError, NotFoundError
 from app.utils.pagination import paginate, sort_query
 
 router = APIRouter(prefix="/units", tags=["units"])
-_procurement_writer = require_role("admin", "procurement_manager")
 
 
 def unit_full_to_dict(unit: Unit) -> dict:
@@ -47,11 +45,7 @@ async def list_units(
 
 
 @router.post("", status_code=201)
-async def create_unit(
-    payload: UnitCreate,
-    db: AsyncSession = Depends(get_db),
-    _auth=Depends(_procurement_writer),
-):
+async def create_unit(payload: UnitCreate, db: AsyncSession = Depends(get_db)):
     duplicate = await db.scalar(select(Unit.id).where(Unit.code == payload.code))
     if duplicate is not None:
         raise ConflictError("واحدی با این کد قبلاً ثبت شده است", field="code")
@@ -76,12 +70,7 @@ async def get_unit(unit_id: int, db: AsyncSession = Depends(get_db)):
 
 
 @router.patch("/{unit_id}")
-async def update_unit(
-    unit_id: int,
-    payload: UnitUpdate,
-    db: AsyncSession = Depends(get_db),
-    _auth=Depends(_procurement_writer),
-):
+async def update_unit(unit_id: int, payload: UnitUpdate, db: AsyncSession = Depends(get_db)):
     unit = await db.get(Unit, unit_id)
     if unit is None:
         raise NotFoundError("واحد یافت نشد")
@@ -103,11 +92,7 @@ async def update_unit(
 
 
 @router.delete("/{unit_id}")
-async def delete_unit(
-    unit_id: int,
-    db: AsyncSession = Depends(get_db),
-    _auth=Depends(_procurement_writer),
-):
+async def delete_unit(unit_id: int, db: AsyncSession = Depends(get_db)):
     unit = await db.get(Unit, unit_id)
     if unit is None:
         raise NotFoundError("واحد یافت نشد")