• feat(types): introduce ResourceNamespaceMap — a separate mergeable augmentation surface for namespace resource types, designed for monorepos where multiple packages each want to contribute their own namespaces. Previously, every package had to coordinate on a single CustomTypeOptions.resources declaration (or fall back to typing dependency namespaces as any) because resources is a single property of an interface and TypeScript reports TS2717 when two declarations of the same property disagree. The new interface merges naturally across declare module 'i18next' blocks, so each package can ship its own i18next.d.ts independently. Per-property merge handles same-namespace contributions from multiple packages, and same-key/different-literal conflicts are silently dropped to avoid poisoning t() overload resolution. Fully backwards-compatible — existing CustomTypeOptions.resources augmentations continue to work, and both surfaces can coexist. Scalar options (defaultNS, returnNull, enableSelector, etc.) still belong on CustomTypeOptions. Thanks @sh3xu (#2434). Fixes #2409.