Remove the organizer's Preview and apply section

The preview/apply flow on the Organize tab did not work as expected, so
it is removed along with its backend: the stored per-pair preview, the
/organize/preview, /organize/plan and /organize/apply endpoints and
their UI and types.

The File naming card stays, and renaming now happens only through
"Organize automatically" during scans, which keeps the underlying
planning/moving code (now internal), undo, crash recovery and dry run.
The rename-folders warning is unchanged. Tests now drive the kept
planning and moving code directly.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/engine/organize_test.go

@@ -60,14 +60,34 @@ func mkTagged(t *testing.T, path string, kv ...string) {
 	}
 }
 
-func (ev *env) organize(t *testing.T, side string) (*OrganizePlan, []OrganizeItem) {
+// plan and apply run the same code as automatic organizing.
+func (ev *env) plan(t *testing.T, sides ...string) *organizePlan {
 	t.Helper()
-	if _, err := ev.e.StartOrganizePlan(ev.pair.ID, side); err != nil {
+	l, err := ev.e.loadPair(ctx, ev.pair.ID)
+	if err != nil {
 		t.Fatal(err)
 	}
-	ev.wait()
-	plan, items, _ := ev.e.OrganizePlanFor(ev.pair.ID, "", 0, 1000)
-	return plan, items
+	p, err := ev.e.planOrganize(ctx, &Job{e: ev.e, Results: map[string]int{}}, l, sides)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return p
+}
+
+func (ev *env) apply(t *testing.T, p *organizePlan) *Job {
+	t.Helper()
+	l, _ := ev.e.loadPair(ctx, ev.pair.ID)
+	j := &Job{e: ev.e, Results: map[string]int{}}
+	var moves []organizeItem
+	for _, it := range p.Items {
+		if it.Move {
+			moves = append(moves, it)
+		}
+	}
+	if err := ev.e.applyOrganize(ctx, j, l, moves, "test"); err != nil {
+		t.Fatal(err)
+	}
+	return j
 }
 
 func TestOrganizeSlaveLibrary(t *testing.T) {
@@ -84,17 +104,14 @@ func TestOrganizeSlaveLibrary(t *testing.T) {
 	mkTagged(t, filepath.Join(s, "dupes/a.mp3"), "title", "Same", "artist", "X", "album", "Y", "track", "1")
 	mkTagged(t, filepath.Join(s, "dupes/b.mp3"), "title", "Same", "artist", "X", "album", "Y", "track", "1")
 
-	plan, items := ev.organize(t, SideSlave)
+	plan := ev.plan(t, SideSlave)
 	if plan.Conforming != 1 || plan.Moves != 2 {
-		t.Fatalf("want 1 conforming and 2 moves, got %+v %+v", plan, items)
+		t.Fatalf("want 1 conforming and 2 moves, got %+v", plan)
 	}
 	if plan.Skips["missing artist or album artist tag"] != 1 || len(plan.Skips) != 2 {
 		t.Fatalf("unexpected skips %+v", plan.Skips)
 	}
-	if _, err := ev.e.StartOrganizeApply(ev.pair.ID, nil); err != nil {
-		t.Fatal(err)
-	}
-	j := ev.wait()
+	j := ev.apply(t, plan)
 	if j.Results["renamed"] != 2 {
 		t.Fatalf("apply: %+v %v", j.Results, j.Skipped)
 	}
@@ -139,11 +156,8 @@ func TestOrganizeKeepsHardlinks(t *testing.T) {
 	if got := ev.match("Chris Picks/Nightmare.flac"); got.Status != store.StatusLinked || got.Kind != store.KindInode {
 		t.Fatalf("a hardlink at another path should be recognised, got %s/%s", got.Status, got.Kind)
 	}
-	ev.organize(t, SideSlave)
-	if _, err := ev.e.StartOrganizeApply(ev.pair.ID, nil); err != nil {
-		t.Fatal(err)
-	}
-	ev.wait()
+	ev.apply(t, ev.plan(t, SideSlave))
+	ev.scan()
 	moved := filepath.Join(ev.slave, "Avenged Sevenfold/Nightmare/01 Nightmare.flac")
 	if !sameInode(t, m, moved) {
 		t.Fatal("the moved slave file must still be the master's file")
@@ -157,11 +171,7 @@ func TestOrganizeDryRunAndChangedFile(t *testing.T) {
 	ev := tagEnv(t, true)
 	p := filepath.Join(ev.slave, "x/song.mp3")
 	mkTagged(t, p, "title", "Song", "artist", "A", "album", "B", "track", "1")
-	ev.organize(t, SideSlave)
-	if _, err := ev.e.StartOrganizeApply(ev.pair.ID, nil); err != nil {
-		t.Fatal(err)
-	}
-	if j := ev.wait(); j.Results["renamed"] != 1 {
+	if j := ev.apply(t, ev.plan(t, SideSlave)); j.Results["renamed"] != 1 {
 		t.Fatalf("dry run should plan the rename: %+v", j.Results)
 	}
 	if _, err := os.Stat(p); err != nil {
@@ -169,11 +179,10 @@ func TestOrganizeDryRunAndChangedFile(t *testing.T) {
 	}
 
 	ev.st.SetSetting(ctx, "dry_run", "0")
-	ev.organize(t, SideSlave)
+	plan := ev.plan(t, SideSlave)
 	mkTagged(t, p, "title", "Song", "artist", "A", "album", "B", "track", "1", "genre", "changed")
-	ev.e.StartOrganizeApply(ev.pair.ID, nil)
-	if j := ev.wait(); j.Results["renamed"] != 0 || j.Results["skipped"] != 1 {
-		t.Fatalf("a file changed after the preview must be skipped: %+v", j.Results)
+	if j := ev.apply(t, plan); j.Results["renamed"] != 0 || j.Results["skipped"] != 1 {
+		t.Fatalf("a file changed after planning must be skipped: %+v", j.Results)
 	}
 }