Create xrpc/atproto.rs module with minimal XRPC endpoint types for: - com.atproto.repo.listRecords - com.atproto.repo.getRecord - com.atproto.identity.resolveHandle - com.atproto.identity.resolveDid These types are vendored in jacquard-common to break circular dependencies between jacquard-lexgen/jacquard-identity and jacquard-api. Implements XrpcRequest/XrpcResp traits and manual IntoStatic impls (cannot use jacquard_derive::IntoStatic due to lack of jacquard-derive dependency). Includes 10 unit tests verifying serialization, deserialization, and IntoStatic trait implementation for all types.