Merge prod-v8 (multi-project allocation, inter-project transfers) into the all-branches integration

Conflicts (all keep-both):
- init_db.py: v7 added ensure_bot_drafts_table, v8 added
  ensure_project_transfers_table at the same anchor — both functions and
  both startup calls kept
- main.py: same, both ensure calls kept
- ChangeInventoryPage.canSubmit: v9's WITHDRAWAL branch and v8's
  PROJECT_TRANSFER branch — both validation branches kept

backend/app/main.py

@@ -32,6 +32,7 @@ from app.db.init_db import (
     ensure_dashboard_tables,
     ensure_material_topic_column,
     ensure_quote_projects,
+    ensure_project_transfers_table,
     ensure_v26,
 )
 from app.observability import RequestContextMiddleware, setup_logging
@@ -109,6 +110,7 @@ async def lifespan(_app: FastAPI):
     await ensure_audit_table(engine)
     await ensure_drop_category_tables(engine)
     await ensure_bot_drafts_table(engine)
+    await ensure_project_transfers_table(engine)
     task = asyncio.create_task(_auto_expire_loop()) if settings.AUTO_EXPIRE_ENABLED else None
     try:
         yield