fix: read/write global CLAUDE.md via WSL on Windows (#264)

## Summary

- `get_global_claude_md` and `save_global_claude_md` were using `dirs::home_dir()` which resolves to the Windows home directory (`C:\Users\accou`) on Windows builds
- The actual `~/.claude/CLAUDE.md` lives in the WSL home directory, so the editor was always showing an empty text box and would have written to the wrong location on save
- Added `get_global_claude_md_via_wsl()` and `save_global_claude_md_via_wsl()` helpers that shell out to WSL (matching the existing pattern used by `list_skills` and `list_memory_files`)
- Both Tauri commands now branch on `cfg!(target_os = "windows")` to use the appropriate path

## Test plan

- [ ] Open Settings sidebar on a Windows build — Global Instructions textarea should load the contents of `~/.claude/CLAUDE.md` from WSL
- [ ] Edit the content and click Save — verify the WSL file is updated
- [ ] Verify Linux/macOS builds are unaffected (native filesystem path unchanged)

✨ This issue was created with help from Hikari~ 🌸

Reviewed-on: #264
Co-authored-by: Hikari <hikari@nhcarrigan.com>
Co-committed-by: Hikari <hikari@nhcarrigan.com>

src-tauri/src/commands.rs

@@ -2618,37 +2618,101 @@ pub async fn open_binary_file(app: AppHandle, path: String) -> Result<(), String
     }
 }
 
+/// Read `~/.claude/CLAUDE.md` via WSL (for Windows).
+/// Returns an empty string if the file does not exist.
+#[cfg(target_os = "windows")]
+async fn get_global_claude_md_via_wsl() -> Result<String, String> {
+    use std::process::Command;
+
+    let output = Command::new("wsl")
+        .hide_window()
+        .args(["-e", "bash", "-l", "-c", "cat ~/.claude/CLAUDE.md 2>/dev/null || true"])
+        .output()
+        .map_err(|e| format!("Failed to execute WSL command: {}", e))?;
+
+    Ok(String::from_utf8_lossy(&output.stdout).to_string())
+}
+
+/// Write content to `~/.claude/CLAUDE.md` via WSL (for Windows).
+/// Creates the file (and `~/.claude/` directory) if they do not exist.
+#[cfg(target_os = "windows")]
+async fn save_global_claude_md_via_wsl(content: String) -> Result<(), String> {
+    use std::io::Write;
+    use std::process::{Command, Stdio};
+
+    let mut child = Command::new("wsl")
+        .hide_window()
+        .args([
+            "-e",
+            "bash",
+            "-l",
+            "-c",
+            "mkdir -p ~/.claude && cat > ~/.claude/CLAUDE.md",
+        ])
+        .stdin(Stdio::piped())
+        .spawn()
+        .map_err(|e| format!("Failed to execute WSL command: {}", e))?;
+
+    if let Some(stdin) = child.stdin.as_mut() {
+        stdin
+            .write_all(content.as_bytes())
+            .map_err(|e| format!("Failed to write content to WSL stdin: {}", e))?;
+    }
+
+    let status = child
+        .wait()
+        .map_err(|e| format!("Failed to wait for WSL command: {}", e))?;
+
+    if !status.success() {
+        return Err("Failed to save CLAUDE.md via WSL".to_string());
+    }
+
+    Ok(())
+}
+
 /// Read the contents of `~/.claude/CLAUDE.md`.
 /// Returns an empty string if the file does not exist.
 #[tauri::command]
 pub async fn get_global_claude_md() -> Result<String, String> {
-    let path = dirs::home_dir()
-        .ok_or_else(|| "Could not determine home directory".to_string())?
-        .join(".claude")
-        .join("CLAUDE.md");
+    #[cfg(target_os = "windows")]
+    return get_global_claude_md_via_wsl().await;
 
-    if !path.exists() {
-        return Ok(String::new());
+    #[cfg(not(target_os = "windows"))]
+    {
+        let path = dirs::home_dir()
+            .ok_or_else(|| "Could not determine home directory".to_string())?
+            .join(".claude")
+            .join("CLAUDE.md");
+
+        if !path.exists() {
+            return Ok(String::new());
+        }
+
+        std::fs::read_to_string(&path).map_err(|e| format!("Failed to read CLAUDE.md: {}", e))
     }
-
-    std::fs::read_to_string(&path).map_err(|e| format!("Failed to read CLAUDE.md: {}", e))
 }
 
 /// Write content to `~/.claude/CLAUDE.md`.
 /// Creates the file (and `~/.claude/` directory) if they do not exist.
 #[tauri::command]
 pub async fn save_global_claude_md(content: String) -> Result<(), String> {
-    let claude_dir = dirs::home_dir()
-        .ok_or_else(|| "Could not determine home directory".to_string())?
-        .join(".claude");
+    #[cfg(target_os = "windows")]
+    return save_global_claude_md_via_wsl(content).await;
 
-    if !claude_dir.exists() {
-        std::fs::create_dir_all(&claude_dir)
-            .map_err(|e| format!("Failed to create ~/.claude directory: {}", e))?;
+    #[cfg(not(target_os = "windows"))]
+    {
+        let claude_dir = dirs::home_dir()
+            .ok_or_else(|| "Could not determine home directory".to_string())?
+            .join(".claude");
+
+        if !claude_dir.exists() {
+            std::fs::create_dir_all(&claude_dir)
+                .map_err(|e| format!("Failed to create ~/.claude directory: {}", e))?;
+        }
+
+        let path = claude_dir.join("CLAUDE.md");
+        std::fs::write(&path, content).map_err(|e| format!("Failed to write CLAUDE.md: {}", e))
     }
-
-    let path = claude_dir.join("CLAUDE.md");
-    std::fs::write(&path, content).map_err(|e| format!("Failed to write CLAUDE.md: {}", e))
 }
 
 #[cfg(test)]