- Remove legacy `Store` type with `Promise<Hash>` `put`; rename `OcasStore` → `Store`
across @ocas/core, @ocas/fs, @ocas/cli (production + tests).
- Migrate `BootstrapCapableStore` to `CasStore`; `[BOOTSTRAP_STORE]` returns `Hash`
synchronously.
- Make `bootstrap()` and `putSchema()` synchronous; remove `await` at all call sites.
- Extract pure VarStore helpers into `packages/core/src/var-store-helpers.ts`
(`varKey`, `addNameIndex`, `removeNameIndex`, `extractSchema`, `checkTagLabelConflict`,
`pushHistory`, `cloneVarRecord`, `VarRecord`); both `MemoryVarStore` (-74 lines) and
`FsVarStore` (-63 lines) now delegate to them while keeping persistence separate.
Refs #47