Fix assertValidCwd to only map NotFound errors to TerminalCwdError

Previously, all fileSystem.stat failures were unconditionally mapped to
TerminalCwdError with reason 'notFound', including permission-denied and
other IO errors. This made non-ENOENT failures impossible to diagnose.

Now only PlatformError with reason._tag 'NotFound' produces the
TerminalCwdError; all other stat errors are re-raised as defects,
matching the original pre-refactor behavior that checked for ENOENT.

Author: cursoragent

apps/server/src/terminal/Layers/Manager.ts

@@ -977,13 +977,16 @@ export const makeTerminalManagerWithOptions = Effect.fn("makeTerminalManagerWith
 
     const assertValidCwd = Effect.fn("terminal.assertValidCwd")(function* (cwd: string) {
       const stats = yield* fileSystem.stat(cwd).pipe(
-        Effect.mapError(
-          (cause) =>
-            new TerminalCwdError({
-              cwd,
-              reason: "notFound",
-              cause,
-            }),
+        Effect.catch((error) =>
+          error.reason._tag === "NotFound"
+            ? Effect.fail(
+                new TerminalCwdError({
+                  cwd,
+                  reason: "notFound",
+                  cause: error,
+                }),
+              )
+            : Effect.die(error),
         ),
       );
       if (stats.type !== "Directory") {