fix: align reflected shapes with Serde behavior

[tisonkun]

Summary

• infer shape bounds on generic parameters and associated values so recursive generic derives do not create cyclic trait obligations
• resolve the actual Cargo dependency name from derive expansions, including renamed serde-shape dependencies
• identify graph definitions by the concrete builder type plus diagnostic Rust name instead of trusting type_name as a unique key
• align byte-slice and network-address shapes with Serde calls, representing readable and compact network forms as unions
• add built-in shapes for Result, Duration, and tuples through Serde's arity 16, with a documented support matrix

Design notes

std::net types use the existing ShapeRef::Union model rather than introducing a serializer-format context. Their string and compact enum/array/tuple forms are both visible to format-agnostic consumers.

Named definitions now use TypeId of the stable builder closure as their source identity, with the Rust type name retained as a specialization and diagnostic value. This prevents same-named types from different crate instances from being silently merged. The builder is consequently required to be 'static.

The derive compile fixture intentionally depends on serde-shape through a renamed Cargo dependency. Serde token tests record the readable and compact calls for byte slices and network types.

This PR does not add description/doc-comment metadata, a generic graph walker, or field-level shape override attributes; those are independent feature designs rather than correctness fixes. Unsupported foreign types remain addressable through documented local newtypes and manual shape implementations.

Validation

• cargo x build --locked
• cargo x test
• cargo x lint