tinyagents-language: three test suites are orphaned since the crate split and never compile

[senamakel]

Problem

crates/tinyagents-language/src/test/mod.rs declares seven modules, but the directory holds ten files. These three are never compiled or run:

• src/test/graph_materialisation.rs
• src/test/registry_binding.rs
• src/test/resolver.rs

They are leftovers from the crate split in 612ea5e (refactor: split tinyagents into focused crates). Adding mod lines is not enough: registry_binding.rs imports crate::registry::CapabilityRegistry, which now lives in tinyagents-registry, and graph_materialisation.rs exercises graph materialisation that now lives in tinyagents-graph's language module. Neither crate is a dependency of tinyagents-language, and adding them would create a dependency cycle (tinyagents-graph depends on tinyagents-language).

Suggested fix

• resolver.rs: likely only needs a mod resolver; line — it imports only crate::source and crate::resolver. Verify it still passes.
• registry_binding.rs and graph_materialisation.rs: move to crates/tinyagents-integration-tests/tests/ (which already covers cross-crate registry binding and graph routing) or delete if they duplicate coverage there.

Noted in the "Known gap" section of crates/tinyagents-language/src/README.md added by #162.

[tinysweeper]

Three test suites in tinyagents-language are orphaned and never compile due to crate split dependencies.

Labelled priority: p2.