avoid generating duplicate stream and future constructors (#206)

Previously, we used the payload type to avoid generating duplicates, but that
doesn't work reliably because `wit-parser` does not necessarily deduplicate
types involving aliases, such as the following example:

```
interface types {
  variant foo {
    bar,
    baz
  }
}

interface use-types-a {
  use types.{foo};

  test: func() -> future<result<foo>>;
}

interface use-types-b {
  use types.{foo};

  test: func() -> future<result<foo>>;
}
```

When targetting a world which imports and/or exports both `use-types-a` and
`use-types-b`, we'll end up with distinct type IDs for `result<foo>`.

This commit switches to using `wit-bindgen-core` to determine the "canonical"
type of the payload and then use that as the deduplication key.  This unblocks
using `wasi:cli@0.3.0-rc-2026-02-09`, which has a similar pattern to the above
WIT example.

Note that this is awkward to test given our current test infra, but #205 will
cover it once it's merged.

Author: dicej

Cargo.lock

@@ -14,11 +14,11 @@ clap = { version = "4.5.20", features = ["derive"] }
 tar = "0.4.42"
 tempfile = "3.13.0"
 zstd = "0.13.2"
-wasm-encoder = { version = "0.244.0", features = ["wasmparser"] }
-wit-dylib = "0.244.0"
-wit-parser = "0.244.0"
-wit-component = "0.244.0"
-wasmparser = "0.244.0"
+wasm-encoder = { version = "0.245.0", features = ["wasmparser"] }
+wit-dylib = "0.245.0"
+wit-parser = "0.245.0"
+wit-component = "0.245.0"
+wasmparser = "0.245.0"
 indexmap = "2.6.0"
 bincode = "1.3.3"
 heck = "0.5.0"
@@ -45,6 +45,7 @@ im-rc = "15.1.0"
 serde = { version = "1.0.213", features = ["derive"] }
 toml = "0.8.19"
 semver = "1.0.23"
+wit-bindgen-core = "0.53.1"
 
 [dev-dependencies]
 assert_cmd = "2.0.16"

Cargo.toml

@@ -372,7 +372,7 @@ pub async fn componentize(
         docs: Default::default(),
         stability: Stability::Unknown,
         includes: Default::default(),
-        include_names: Default::default(),
+        span: Default::default(),
     });
 
     resolve.packages[union_package]
@@ -803,7 +803,7 @@ fn add_wasi_and_stubs(
                         .or_default()
                         .push(Stub::Function(&function.name, &function.kind));
                 }
-                WorldItem::Type(id) => {
+                WorldItem::Type { id, .. } => {
                     let ty = &resolve.types[*id];
                     if let TypeDefKind::Resource = &ty.kind {
                         stubs