feat(lsp): add workspace symbol search

Assisted-by: MiMo V2.5 Pro

lsp/server_test.go

@@ -450,6 +450,31 @@ func TestDocumentHighlights(t *testing.T) {
 	}
 }
 
+func TestWorkspaceSymbols(t *testing.T) {
+	in := session("file:///f_amd64.s", cleanDoc) +
+		frame(13, "workspace/symbol", map[string]any{
+			"query": "foo",
+		}) + frame(nil, "exit", nil)
+	msgs := run(t, in)
+	resp := findByID(msgs, 13)
+	if resp == nil {
+		t.Fatal("no workspace/symbol response")
+	}
+	var syms []WorkspaceSymbol
+	if err := json.Unmarshal(mustResult(t, resp), &syms); err != nil {
+		t.Fatal(err)
+	}
+	found := false
+	for _, s := range syms {
+		if s.Name == "foo" {
+			found = true
+		}
+	}
+	if !found {
+		t.Fatalf("want symbol foo in results, got %+v", syms)
+	}
+}
+
 func TestMethodNotFound(t *testing.T) {
 	in := frame(9, "bogus/method", map[string]any{}) + frame(nil, "exit", nil)
 	msgs := run(t, in)