controller v0.242.0: a removed app is listed with its kept backup; five small ones (R-487 R-491 R-490 R-489 R-476 R-456)

R-487: the local backup lists are keyed on the drives, not on what is
deployed — a removed app whose unit was kept is listed with the restore
that reinstalls it, the picker answers for it, and the restore opens the
unit where it sits. R-491: a removal clears the app's update hold.
R-490: /api/system/info reaches the API router and reads the default
storage path. R-489: volumes_removed is the real before/after difference,
[] when none. R-476: a Tier-2 copy is dated by its data, not its manifest.
R-456: the boot-orphan rule is pinned. Every fix red-proofed.

controller/internal/api/r474_remove_wiring_test.go

@@ -1,9 +1,13 @@
 package api
 
 import (
+	"encoding/json"
+	"gitea.dooplex.hu/admin/felhom-controller/internal/settings"
 	"go/ast"
 	"go/parser"
 	"go/token"
+	"net/http"
+	"net/http/httptest"
 	"strings"
 	"testing"
 )
@@ -60,3 +64,58 @@ func TestR486_RemovalKeepsTheTier2RecordUnlessBackupsGo(t *testing.T) {
 		})
 	}
 }
+
+// R-491 — a removal clears the app's UPDATE hold (and only that kind).
+//
+// COMPANION RED-PROOF (REPORT.md): remove the ClearUpdateHold call from removeStack — this fails.
+func TestR491_RemovalClearsTheUpdateHold(t *testing.T) {
+	fset := token.NewFileSet()
+	f, err := parser.ParseFile(fset, "router.go", nil, 0)
+	if err != nil {
+		t.Fatal(err)
+	}
+	found := false
+	for _, d := range f.Decls {
+		fn, ok := d.(*ast.FuncDecl)
+		if !ok || fn.Name.Name != "removeStack" || fn.Body == nil {
+			continue
+		}
+		ast.Inspect(fn.Body, func(n ast.Node) bool {
+			if s, ok := n.(*ast.SelectorExpr); ok && s.Sel.Name == "ClearUpdateHold" {
+				found = true
+			}
+			return true
+		})
+	}
+	if !found {
+		t.Error("removeStack must clear the app's update hold (R-491), or a reinstall starts held")
+	}
+}
+
+// R-490 — with a default storage path registered, system-info reports the drive (the fallback every
+// other reader already had).
+func TestR490_SystemInfoFallsBackToTheDefaultStoragePath(t *testing.T) {
+	r, sett, _, _ := newSlice4Router(t)
+	r.sett = sett // the fixture router carries no settings; system-info reads the default path from them
+	if err := sett.AddStoragePath(settings.StoragePath{Path: t.TempDir(), Label: "HDD", Schedulable: true, IsDefault: true}); err != nil {
+		t.Fatal(err)
+	}
+	w := httptest.NewRecorder()
+	r.ServeHTTP(w, httptest.NewRequest(http.MethodGet, "/api/system/info", nil))
+	if w.Code != http.StatusOK {
+		t.Fatalf("status %d: %s", w.Code, w.Body.String())
+	}
+	var resp struct {
+		Data struct {
+			System struct {
+				HDDConfigured bool `json:"hdd_configured"`
+			} `json:"system"`
+		} `json:"data"`
+	}
+	if err := json.Unmarshal(w.Body.Bytes(), &resp); err != nil {
+		t.Fatal(err)
+	}
+	if !resp.Data.System.HDDConfigured {
+		t.Errorf("hdd_configured must be true with a default storage path registered; body %s", w.Body.String())
+	}
+}