Frontend: Inertia page props are hand-typed and force-cast (44 as unknown as) #505

Tier 2: structural

Problem

There are 44 as unknown as casts and 42 usePage<{ props: X }>() calls, usually followed by .props as unknown as X. Examples: host/client_app/pages/Admin.tsx:55, Landing.tsx:41, modules/api_tokens/.../Admin.tsx:23, modules/background_tasks/.../Index.tsx:73.

A double cast turns type checking off. If a Python view renames a prop, tsc still passes and the page breaks at runtime. Nothing checks that a page's prop type matches what inertia.render(...) passes.

Proposal

• Short term: add a usePageProps<T>() helper to packages/ui and remove the double casts.
• Proper fix: have each view declare its props as a SQLModel DTO, then generate a PageProps map (page name → props type) at gen-pages time, as is already done for the page manifest. SM003/SM004 already link page names to renders, so the hook point exists.

Depends on or pairs with the typed API client issue.