fix: add openCodePromptEnv, fix test, gofumpt

Author: Patel230

e2e/agents/opencode.go

@@ -166,3 +166,7 @@ func (a *openCodeAgent) StartSession(ctx context.Context, dir string) (Session,
 	}
 	return nil, fmt.Errorf("opencode TUI failed to start after retry: %w", lastErr)
 }
+
+func openCodePromptEnv(base []string, dir string) []string {
+	return append(filterEnv(base, "TRACE_TEST_TTY", "PWD"), "PWD="+dir)
+}

e2e/agents/opencode_test.go

@@ -15,7 +15,7 @@ func TestOpenCodePromptEnv_OverridesPWD(t *testing.T) {
 	t.Parallel()
 	base := []string{
 		"PWD=/some/stale/go-test/dir",
-		"ENTIRE_TEST_TTY=1",
+		"TRACE_TEST_TTY=1",
 		"HOME=/home/runner",
 	}
 
@@ -40,9 +40,9 @@ func TestOpenCodePromptEnv_OverridesPWD(t *testing.T) {
 		t.Fatalf("expected exactly one PWD entry, got %d", count)
 	}
 
-	// ENTIRE_TEST_TTY is still stripped so the agent exercises real TTY detection.
-	if got, ok := envValue(env, "ENTIRE_TEST_TTY"); ok {
-		t.Fatalf("ENTIRE_TEST_TTY = %q, want stripped", got)
+	// TRACE_TEST_TTY is still stripped so the agent exercises real TTY detection.
+	if got, ok := envValue(env, "TRACE_TEST_TTY"); ok {
+		t.Fatalf("TRACE_TEST_TTY = %q, want stripped", got)
 	}
 
 	// Unrelated env is preserved.