feat(gateway): admin 列表端点接真实数据——persona/session/memory 补 List() 并注入 gateway.Deps

根因：gateway.Server 定义 SessionStore/PersonaStore/MemoryStore 接口但生产从未满足：
- 底层 manager 无 List() 方法；
- wireFrontend 的 gateway.Deps{} 未传 Session/Personas/Memories。
→ /api/v1/sessions|personas 与 /api/v1/admin/{sessions,personas,memories} 恒返回 []。

改动：
- persona/registry：Registry.List() []Character（并发安全、值拷贝）。
- channel/session：SessionManager.List(ctx)（查 channel_sessions 表+按 actor_role 重建）。
- runtime/memory：Store.List(ctx)（全表，复用 scanItems）。
- gateway 三 Store 接口改为返回域类型（Character/MemoryItem），映射统一放 collect* 侧。
- cmd/cyrene/wire.go：Deps 补传 Session/Personas/Memories。
- .gitignore：cyrene→/cyrene（锚定根，不再误伤 cmd/cyrene 目录）。

实机验证：/api/v1/admin/personas 返回 {id:cyrene,name:昔涟,isDefault:true}。

internal/channel/session/manager_test.go

@@ -207,6 +207,94 @@ func TestGetOrCreateConcurrent(t *testing.T) {
 	}
 }
 
+func TestList(t *testing.T) {
+	t.Parallel()
+
+	m, _ := newTestManager(t)
+	ctx := context.Background()
+
+	if _, err := m.GetOrCreate(ctx, directMsg("o-100"), testOwner()); err != nil {
+		t.Fatalf("GetOrCreate(owner): %v", err)
+	}
+	if _, err := m.GetOrCreate(ctx, directMsg("stranger-1"), testOwner()); err != nil {
+		t.Fatalf("GetOrCreate(stranger): %v", err)
+	}
+	if _, err := m.GetOrCreate(ctx, groupMsg("g-member-1"), testOwner()); err != nil {
+		t.Fatalf("GetOrCreate(group): %v", err)
+	}
+
+	got, err := m.List(ctx)
+	if err != nil {
+		t.Fatalf("List: %v", err)
+	}
+	if len(got) != 3 {
+		t.Fatalf("List = %d sessions, want 3", len(got))
+	}
+	var owner, stranger, group bool
+	for _, s := range got {
+		switch s.ChannelID {
+		case "direct-o-100":
+			if !s.Owner || !s.MemWritable || s.IsGroup {
+				t.Errorf("owner session flags = %+v, want owner/writable/not-group", s)
+			}
+			owner = true
+		case "direct-stranger-1":
+			if s.Owner || s.MemWritable || s.IsGroup {
+				t.Errorf("stranger session flags = %+v, want non-owner/read-only/not-group", s)
+			}
+			stranger = true
+		case groupChannelPrefix + "g1":
+			if !s.IsGroup || s.MemWritable {
+				t.Errorf("group session flags = %+v, want group/read-only", s)
+			}
+			group = true
+		}
+	}
+	if !owner || !stranger || !group {
+		t.Fatalf("missing sessions: owner=%v stranger=%v group=%v", owner, stranger, group)
+	}
+}
+
+func TestListRecoveredFromTable(t *testing.T) {
+	t.Parallel()
+
+	ctx := context.Background()
+	handle, err := db.Open(ctx, ":memory:", nil)
+	if err != nil {
+		t.Fatalf("db.Open = %v", err)
+	}
+	t.Cleanup(func() { _ = handle.Close() })
+
+	m1, err := New(ctx, handle, nil)
+	if err != nil {
+		t.Fatalf("New#1 = %v", err)
+	}
+	if _, err := m1.GetOrCreate(ctx, directMsg("o-100"), testOwner()); err != nil {
+		t.Fatalf("m1.GetOrCreate = %v", err)
+	}
+
+	// A brand-new manager over the same DB has an empty cache: List must
+	// reconstruct the session from the backing table (cross-restart path).
+	m2, err := New(ctx, handle, nil)
+	if err != nil {
+		t.Fatalf("New#2 = %v", err)
+	}
+	got, err := m2.List(ctx)
+	if err != nil {
+		t.Fatalf("List = %v", err)
+	}
+	if len(got) != 1 {
+		t.Fatalf("List = %d sessions, want 1", len(got))
+	}
+	s := got[0]
+	if s.ChannelID != "direct-o-100" || s.SessionID == "" {
+		t.Fatalf("recovered session = %+v, want direct-o-100", s)
+	}
+	if !s.Owner || !s.MemWritable {
+		t.Errorf("recovered owner flags = %+v, want owner/writable", s)
+	}
+}
+
 func TestGetOrCreateInvalidChannel(t *testing.T) {
 	t.Parallel()