perry/container & perry/compose calls compile to undefined — NativeMethodCall reaches no js_container_* symbol (JS surface dead) #11211

Found while working on tokio lane K (#11209). A compiled Perry program cannot call the perry/container / perry/compose APIs at all. It fails the same way on main and on #11209.

A probe calls getBackend(), await listImages(), and await up({...}) / down() against a stub docker on PATH. It compiles and links: auto-optimize selects features=async-bridge,container, and the archive contains the container code. But every call evaluates to undefined, and the stub docker is never invoked.

HIR lowers these calls to NativeMethodCall { module: "perry/container", method: "getBackend" }, which apparently reaches no js_container_* symbol in codegen.

Consequences:

• The JS-facing container surface is effectively dead.
• Only the stdlib FFI tests cover the bridge.
• There are no perry/container gap tests: --filter container|compose|workload matches nothing relevant. That is why this went unnoticed.

Fix: wire the perry/container, perry/compose and perry/workloads NativeMethodCalls to the js_container_* / compose FFI exports. Add gap tests that run against a stub docker binary on PATH, so they need no real container runtime, and assert that the stub was actually invoked.