feat(cli): Restore packages from webcs

lib/config/src/package/mod.rs

@@ -185,6 +185,10 @@ pub struct Package {
 }
 
 impl Package {
+    pub fn new_empty() -> Self {
+        PackageBuilder::default().build().unwrap()
+    }
+
     /// Create a [`PackageBuilder`] populated with all mandatory fields.
     pub fn builder(
         name: impl Into<String>,
@@ -732,6 +736,16 @@ pub struct Manifest {
 }
 
 impl Manifest {
+    pub fn new_empty() -> Self {
+        Self {
+            package: None,
+            dependencies: HashMap::new(),
+            fs: IndexMap::new(),
+            modules: Vec::new(),
+            commands: Vec::new(),
+        }
+    }
+
     /// Create a [`ManifestBuilder`] populated with all mandatory fields.
     pub fn builder(package: Package) -> ManifestBuilder {
         ManifestBuilder::new(package)

lib/package/src/convert/error.rs

@@ -0,0 +1,39 @@
+use std::sync::Arc;
+
+#[derive(Clone, Debug)]
+pub struct ManifestConversionError {
+    message: String,
+    cause: Option<Arc<dyn std::error::Error + Send + Sync>>,
+}
+
+impl ManifestConversionError {
+    pub fn msg(msg: impl Into<String>) -> Self {
+        Self {
+            message: msg.into(),
+            cause: None,
+        }
+    }
+
+    pub fn with_cause(
+        msg: impl Into<String>,
+        cause: impl std::error::Error + Send + Sync + 'static,
+    ) -> Self {
+        Self {
+            message: msg.into(),
+            cause: Some(Arc::new(cause)),
+        }
+    }
+}
+
+impl std::fmt::Display for ManifestConversionError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "could not convert manifest: {}", self.message)?;
+        if let Some(cause) = &self.cause {
+            write!(f, " (cause: {})", cause)?;
+        }
+
+        Ok(())
+    }
+}
+
+impl std::error::Error for ManifestConversionError {}

lib/package/src/convert/mod.rs

@@ -0,0 +1,4 @@
+mod error;
+mod webc_to_package;
+
+pub use self::{error::ManifestConversionError, webc_to_package::webc_to_package_dir};