refactor: make workspace API own workdir projections

crates/workspace-api/src/lib.rs

@@ -113,10 +113,11 @@ pub struct Diagnostic {
 ///
 /// The value identifies stable materialization provenance without exposing a
 /// provider path, Runtime handle, or session identity.
-#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
+#[derive(Debug, Clone, Copy, Default, Serialize, Deserialize, PartialEq, Eq)]
 #[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
 #[serde(rename_all = "snake_case")]
 pub enum WorkingDirectoryMaterializerKind {
+    #[default]
     RuntimeGitCache,
     LocalGitWorktree,
 }
@@ -132,15 +133,21 @@ pub enum WorkingDirectoryStatusKind {
     Unknown,
 }
 
-impl std::fmt::Display for WorkingDirectoryStatusKind {
-    fn fmt(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        formatter.write_str(match self {
+impl WorkingDirectoryStatusKind {
+    pub const fn as_str(&self) -> &'static str {
+        match self {
             Self::Active => "active",
             Self::CleanupPending => "cleanup_pending",
             Self::Corrupted => "corrupted",
             Self::NotFound => "not_found",
             Self::Unknown => "unknown",
-        })
+        }
+    }
+}
+
+impl std::fmt::Display for WorkingDirectoryStatusKind {
+    fn fmt(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        formatter.write_str(self.as_str())
     }
 }
 
@@ -199,6 +206,13 @@ pub struct WorkingDirectorySummary {
     pub occupied_by: Option<WorkingDirectoryOccupancy>,
 }
 
+impl WorkingDirectorySummary {
+    /// Workspace-managed inventory rows carry explicit cleanup authority.
+    pub fn is_workspace_managed(&self) -> bool {
+        self.cleanup_target.is_some()
+    }
+}
+
 /// Browser/Rust-client Workdir materialization request.
 ///
 /// `runtime_id = None` requests Workspace default Runtime resolution and