Ingest-path stores use `as unknown as IfcDataStore` and skip IfcStoreBase accessors

[louistrue]

Split out from #952 (now resolved/closed). The cache-reopen cast bridge was fixed in #993 (typed hydrateCacheStore) and the wasm-free typecheck lane landed in #1002 — but the same duck-typing pattern #952 condemned still lives in the ingest paths:

• apps/viewer/src/hooks/ingest/viewerModelIngest.ts — createMinimalGlbDataStore() builds a store via a whole-object as unknown as IfcDataStore cast (plus per-field casts).
• apps/viewer/src/hooks/ingest/pointCloudIngest.ts — same pattern.

These synthetic stores lack the IfcStoreBase accessors (getEntity / getEntitiesByType / getProperties / getQuantities) and never call attachDataStoreAccessors, yet they route into the live store via useIfcLoader / ViewportContainer → the query path (new EntityNode(model.ifcDataStore) → store.getProperties()).

Why it matters: same crash class as the original cache-reopen bug (#950). A future required-member addition to IfcDataStore stays silently green at these as unknown as sites and throws TypeError: store.getProperties is not a function at runtime on the GLB / point-cloud ingest flow. It also violates the AGENTS.md house rule (no as any / as unknown as escape hatches — fix the types or add a .d.ts).

Fix: replace the casts with a typed builder (analogous to hydrateCacheStore in useIfcCache.ts) that constructs an IfcStoreData and runs it through attachDataStoreAccessors, so the compiler enforces the full IfcDataStore contract for synthetic GLB/point-cloud stores too.

Context: #952, #950, #993, #1002.