v1.7.6

Migrate Rust examples to SDK 0.11.0 service API (#407)

The Rust SDK 0.11.0 replaces the trait-based service definition with a
struct-based one: the macro (#[service]/#[object]/#[workflow]) goes on
the struct's impl block, each handler is annotated with #[handler], and
shared/exclusive is inferred from the context type. Services are bound
with .bind(Struct) instead of .bind(StructImpl.serve()).

Updates all examples in rust/basics and both rust/templates. Service and
handler names are preserved, so HTTP endpoints and generated clients
(e.g. SubscriptionServiceClient) are unchanged.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>