feat(maestro): GET /api/branches — local branches and worktree occupancy (#55)

crates/maestro-protocol/src/lib.rs

@@ -212,6 +212,21 @@ pub struct Project {
     pub last_command: Option<String>,
 }
 
+/// One local branch of a repository for `GET /api/branches` (#55). A client
+/// disables the entry when `is_head` is set or `worktree` is present — git
+/// refuses to check the same branch out in two worktrees at once.
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+pub struct BranchInfo {
+    /// Short branch name (`main`, `feature/foo`).
+    pub name: String,
+    /// Whether this branch is the main checkout's current HEAD. The main
+    /// checkout's occupancy reports here rather than through `worktree`.
+    pub is_head: bool,
+    /// Toplevel path of the linked worktree holding this branch, if any.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub worktree: Option<PathBuf>,
+}
+
 /// Structured failure used everywhere we don't want to leak a string-only error.
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub struct ErrorInfo {

crates/maestro-protocol/src/routes.rs

@@ -21,10 +21,12 @@ pub const RECENT_DIRS: &str = "/api/recent-dirs";
 pub const PROJECTS: &str = "/api/projects";
 /// `GET` the enclosing repository of a path. Takes a `path` query param.
 pub const GITROOT: &str = "/api/gitroot";
+/// `GET` one repository's local branches. Takes a `path` query param.
+pub const BRANCHES: &str = "/api/branches";
 /// `WS` catalog snapshot + session deltas.
 pub const EVENTS: &str = "/api/events";
 
-/// Name of the query parameter [`DIRS`] and [`GITROOT`] both take.
+/// Name of the query parameter [`DIRS`], [`GITROOT`], and [`BRANCHES`] take.
 pub const PATH_QUERY: &str = "path";
 
 /// `DELETE /api/sessions/:id`.
@@ -174,7 +176,16 @@ mod tests {
 
     #[test]
     fn every_route_sits_under_the_api_prefix() {
-        for path in [SESSIONS, INFO, DIRS, RECENT_DIRS, PROJECTS, GITROOT, EVENTS] {
+        for path in [
+            SESSIONS,
+            INFO,
+            DIRS,
+            RECENT_DIRS,
+            PROJECTS,
+            GITROOT,
+            BRANCHES,
+            EVENTS,
+        ] {
             assert!(path.starts_with(API_PREFIX), "{path} escapes {API_PREFIX}");
         }
         assert!(attach(id()).starts_with(API_PREFIX));