fix(review round 2): daemon symlink tars, orphan-safe removes, unique seed names, git ctx, IsErrNotFound, collision-free slugs, branch validation; web first-run WS, draft reset, IME guard, churn fix, test swap repair; 106 daemon + 190 web tests green

daemon/api_test.go

@@ -106,16 +106,33 @@ func TestAPIEventsReplayShape(t *testing.T) {
 
 func TestAPISpawnValidation(t *testing.T) {
 	ts, _ := newTestServer(t)
-	req, _ := http.NewRequest(http.MethodPost, ts.URL+"/api/spawn",
-		strings.NewReader(`{"repo":"no-slash"}`))
-	req.Header.Set("Authorization", "Bearer "+testToken)
-	resp, err := http.DefaultClient.Do(req)
-	if err != nil {
-		t.Fatalf("spawn: %v", err)
+	post := func(body string) int {
+		req, _ := http.NewRequest(http.MethodPost, ts.URL+"/api/spawn", strings.NewReader(body))
+		req.Header.Set("Authorization", "Bearer "+testToken)
+		resp, err := http.DefaultClient.Do(req)
+		if err != nil {
+			t.Fatalf("spawn: %v", err)
+		}
+		resp.Body.Close()
+		return resp.StatusCode
 	}
-	resp.Body.Close()
-	if resp.StatusCode != http.StatusBadRequest {
-		t.Fatalf("bad repo → %d, want 400", resp.StatusCode)
+	if code := post(`{"repo":"no-slash"}`); code != http.StatusBadRequest {
+		t.Fatalf("bad repo → %d, want 400", code)
+	}
+	// branch is passed to git: anything outside the safe charset → 400
+	for _, branch := range []string{
+		"main; rm -rf /",
+		"feature one",      // space
+		"-oProxyCommand=x", // leading option-ish
+		"main$(id)",
+	} {
+		if code := post(`{"repo":"group/project","branch":"` + branch + `"}`); code != http.StatusBadRequest {
+			t.Fatalf("branch %q → %d, want 400", branch, code)
+		}
+	}
+	// empty branch (default) stays accepted at this validation layer
+	if code := post(`{"repo":"group/project","branch":""}`); code == http.StatusBadRequest {
+		t.Fatal("empty branch must not be rejected as invalid")
 	}
 }