fix(git): add missing refreshGitStatus to stashDrop and handle persistent dirty worktree errors

- Add refreshGitStatus(input.cwd) to the gitStashDrop WS handler so
  clients see updated stash state after a drop, matching all other
  git mutation handlers.
- Detect when stashAndCheckout fails because ignored files still
  conflict (stash -u doesn't capture .gitignore'd files) and show
  an actionable error instead of a confusing dirty-worktree message.

Author: Marve10s

apps/server/src/ws.ts

@@ -798,9 +798,11 @@ const makeWsRpcLayer = (currentSessionId: AuthSessionId) =>
             { "rpc.aggregate": "git" },
           ),
         [WS_METHODS.gitStashDrop]: (input) =>
-          observeRpcEffect(WS_METHODS.gitStashDrop, git.stashDrop(input.cwd), {
-            "rpc.aggregate": "git",
-          }),
+          observeRpcEffect(
+            WS_METHODS.gitStashDrop,
+            git.stashDrop(input.cwd).pipe(Effect.tap(() => refreshGitStatus(input.cwd))),
+            { "rpc.aggregate": "git" },
+          ),
         [WS_METHODS.gitInit]: (input) =>
           observeRpcEffect(
             WS_METHODS.gitInit,

apps/web/src/components/BranchToolbarBranchSelector.tsx

@@ -157,6 +157,13 @@ function handleCheckoutError(
                     },
                   },
                 });
+              } else if (parseDirtyWorktreeError(stashError)) {
+                toastManager.add({
+                  type: "error",
+                  title: "Cannot switch branches.",
+                  description:
+                    "Some conflicting files are not covered by git stash (e.g., files in .gitignore). Remove or move them manually before switching.",
+                });
               } else {
                 toastManager.add({
                   type: "error",