Refactored a few things from main into modules

server/src/io/fs.rs

@@ -379,6 +379,20 @@ To support both Remote and Local models, the system implements a `ModelProvider`
     *   Shell commands that modify state (non-readonly) should ideally require a UI confirmation (configurable).
     *   File writes must be confirmed or revertible."#;
 
+/// Walk from `start` up through parent directories, returning the first
+/// directory that contains a `.story_kit/` subdirectory, or `None`.
+pub fn find_story_kit_root(start: &Path) -> Option<PathBuf> {
+    let mut current = start.to_path_buf();
+    loop {
+        if current.join(".story_kit").is_dir() {
+            return Some(current);
+        }
+        if !current.pop() {
+            return None;
+        }
+    }
+}
+
 pub fn get_home_directory() -> Result<String, String> {
     let home = homedir::my_home()
         .map_err(|e| format!("Failed to resolve home directory: {e}"))?
@@ -960,6 +974,47 @@ mod tests {
         assert!(result.is_ok());
     }
 
+    // --- find_story_kit_root ---
+
+    #[test]
+    fn find_story_kit_root_returns_cwd_when_story_kit_in_cwd() {
+        let tmp = tempfile::tempdir().unwrap();
+        std::fs::create_dir_all(tmp.path().join(".story_kit")).unwrap();
+
+        let result = find_story_kit_root(tmp.path());
+        assert_eq!(result, Some(tmp.path().to_path_buf()));
+    }
+
+    #[test]
+    fn find_story_kit_root_returns_parent_when_story_kit_in_parent() {
+        let tmp = tempfile::tempdir().unwrap();
+        std::fs::create_dir_all(tmp.path().join(".story_kit")).unwrap();
+        let child = tmp.path().join("subdir").join("nested");
+        std::fs::create_dir_all(&child).unwrap();
+
+        let result = find_story_kit_root(&child);
+        assert_eq!(result, Some(tmp.path().to_path_buf()));
+    }
+
+    #[test]
+    fn find_story_kit_root_returns_none_when_no_story_kit() {
+        let tmp = tempfile::tempdir().unwrap();
+
+        let result = find_story_kit_root(tmp.path());
+        assert_eq!(result, None);
+    }
+
+    #[test]
+    fn find_story_kit_root_prefers_nearest_ancestor() {
+        let tmp = tempfile::tempdir().unwrap();
+        std::fs::create_dir_all(tmp.path().join(".story_kit")).unwrap();
+        let child = tmp.path().join("inner");
+        std::fs::create_dir_all(child.join(".story_kit")).unwrap();
+
+        let result = find_story_kit_root(&child);
+        assert_eq!(result, Some(child));
+    }
+
     // --- scaffold ---
 
     #[test]