feat(package): add component and WIT package tooling

- define the constrained .wasmpkg archive and integrity checks\n- encode and inspect standard binary WIT packages\n- resolve exact Registry dependencies with wit.lock and path replace\n- provide wasmeld pack and wit build/fetch/publish CLI commands

crates/wasmeld-package/Cargo.toml

@@ -0,0 +1,25 @@
+[package]
+name = "wasmeld-package"
+version = "0.1.0"
+edition.workspace = true
+rust-version.workspace = true
+license.workspace = true
+
+[dependencies]
+reqwest.workspace = true
+serde.workspace = true
+serde_json.workspace = true
+semver.workspace = true
+sha2.workspace = true
+thiserror.workspace = true
+toml.workspace = true
+wit-component.workspace = true
+wit-parser.workspace = true
+zip.workspace = true
+
+[dev-dependencies]
+tempfile = "3.23.0"
+
+[[bin]]
+name = "wasmeld"
+path = "src/main.rs"