Remove legacy room list (#34040)

* refactor(room-list): migrate SpaceStore off the legacy room list store

SpaceStore.setActiveRoomInSpace iterated the legacy RoomListStore's
`orderedLists` in `TAG_ORDER`; switch it to the space-aware
RoomListStoreV3.getSortedRoomsInActiveSpace() accessor. This drops the
last non-UI dependency on the legacy store and on `TAG_ORDER` (exported
from LegacyRoomList, deleted next).

* feat(room-list)!: remove the legacy room list UI

Delete the old sublist-based room list and its components now that the
new RoomListPanel is the default. Removed: LegacyRoomList,
LegacyRoomListHeader, RoomSublist, ExtraTile, RoomTile (+ Subtitle/
CallSummary), RoomBreadcrumbs and RoomSearch, plus their styles and
tests.

LeftPanel collapses to the RoomListPanel-only path. The shared
`contextMenuBelow` helper is relocated into RoomResultContextMenus (its
only remaining consumer).

* feat(room-list)!: remove the legacy RoomListStore

The legacy sublist-based room list UI is gone, so the old
`stores/room-list` store (Algorithm, sorters, filters, layout store,
space
watcher) has no remaining consumers. Delete the directory and its tests.

MatrixChat.forgetRoom no longer calls the legacy `manualRoomUpdate`; the
new room list store removes the room on the `AfterForgetRoom` dispatch
that still fires. Drop the `mxRoomListStore`/`mxRoomListLayoutStore`
globals and the now-dead test imports.

* feat(room-list)!: remove the feature_new_room_list labs flag

The new room list is now the only room list, so remove the
feature_new_room_list labs flag and make its enabled behaviour
unconditional everywhere it was gated:

- LoggedInView: always use the resizable layout and
NEW_ROOM_LIST_MIN_WIDTH;
  drop the collapsible/minimized legacy path.
- SpaceStore: People and Favourites are dropped from metaSpaceOrder (per
the
  long-standing TODO on the removed accessor).
- MessagePreviewStore: stop appending thread replies to previews.
- Settings, SidebarUserSettingsTab, PreferencesUserSettingsTab,
  QuickSettingsButton, SpacePanel, LandmarkNavigation: drop the flag
reads and
  legacy branches.

Update the tests that toggled the flag; the People/Favourites meta space
tests covered behaviour that the flag (default on) already disabled.

* feat(room-list)!: remove the dead legacy left-panel resizer

LoggedInView still built the old `Resizer`/`CollapseDistributor` over an
`lp-resizer` ResizeHandle and persisted `mx_lhs_size`. That handle is no
longer rendered (the resizable layout is now driven by
LeftResizablePanelView + ResizerViewModel, which persists its own state
via RoomList.panelSize/RoomList.isPanelCollapsed), so the old resizer
was
inert dead code left over from the legacy room list.

Remove createResizer/loadResizer/loadResizerPreferences, the
_resizeContainer/resizeHandler refs, the ResizeHandle render, the
mx_lhs_size handling and NEW_ROOM_LIST_MIN_WIDTH, plus the unit tests
that
exercised the mocked resizer.

* feat(room-list)!: update i18n files

* refactor(room-list): remove the now-unused collapseLhs state

`collapseLhs` is write-only since the left panel no longer collapses: it
was last read by LoggedInView's `shouldUseMinimizedUI`, removed with the
feature_new_room_list flag. Drop it from MatrixChat's IState (and its
assignments), collapsing the hide/show_left_panel handlers to just the
`notifyLeftHandleResized()` call they still need, and from
LoggedInView's
IProps and the test props.

* fix(room-list): instantiate message previewers lazily

Removing the unused SettingsStore import from MessagePreviewStore (when
the
feature_new_room_list flag was dropped) changed module load order and
exposed a latent circular dependency: ReactionEventPreview imports
MessagePreviewStore, which eagerly did `new ReactionEventPreview()` at
module-eval — so importing ReactionEventPreview first (as its unit test
does) hit "ReactionEventPreview is not a constructor".

Construct the previewers lazily on first use (cached) instead of at
module
load, so nothing dereferences a mid-evaluation module. Fixes
ReactionEventPreview-test.

* test(room-list): remove `feature_new_room_list` labs flag in e2e tests

* chore: remove remaining `newRoomList` flag

* chore: cleanup theme files

* fix: restore the re-resizable TouchEvent polyfill

* chore: remove usage of breadcrumbs settings in BreadcrumbStore

* Revert "fix(room-list): instantiate message previewers lazily"

This reverts commit 4e6eedfff0449c68a96c0470a4eb425b5aec5512.

* chore: remove unused function in BreadCrumbStore

* test: remove unused fuction of BreadcrumStore in tests

* test: add tests for RoomResultContextMenu

apps/web/res/css/_components.pcss

@@ -56,7 +56,6 @@
 @import "./compound/_SuccessDialog.pcss";
 @import "./structures/_AutoHideScrollbar.pcss";
 @import "./structures/_AutocompleteInput.pcss";
-@import "./structures/_BackdropPanel.pcss";
 @import "./structures/_CompatibilityPage.pcss";
 @import "./structures/_ContextualMenu.pcss";
 @import "./structures/_ErrorMessage.pcss";
@@ -72,7 +71,6 @@
 @import "./structures/_PictureInPictureDragger.pcss";
 @import "./structures/_QuickSettingsButton.pcss";
 @import "./structures/_RightPanel.pcss";
-@import "./structures/_RoomSearch.pcss";
 @import "./structures/_RoomView.pcss";
 @import "./structures/_SearchBox.pcss";
 @import "./structures/_SpaceHierarchy.pcss";
@@ -259,8 +257,6 @@
 @import "./views/rooms/_IRCLayout.pcss";
 @import "./views/rooms/_InvitedIconView.pcss";
 @import "./views/rooms/_JumpToBottomButton.pcss";
-@import "./views/rooms/_LegacyRoomList.pcss";
-@import "./views/rooms/_LegacyRoomListHeader.pcss";
 @import "./views/rooms/_LiveContentSummary.pcss";
 @import "./views/rooms/_MemberListHeaderView.pcss";
 @import "./views/rooms/_MemberListView.pcss";
@@ -277,15 +273,12 @@
 @import "./views/rooms/_ReadReceiptGroup.pcss";
 @import "./views/rooms/_ReplyPreview.pcss";
 @import "./views/rooms/_ReplyTile.pcss";
-@import "./views/rooms/_RoomBreadcrumbs.pcss";
 @import "./views/rooms/_RoomHeader.pcss";
 @import "./views/rooms/_RoomInfoLine.pcss";
 @import "./views/rooms/_RoomKnocksBar.pcss";
 @import "./views/rooms/_RoomPreviewBar.pcss";
 @import "./views/rooms/_RoomPreviewCard.pcss";
 @import "./views/rooms/_RoomSearchAuxPanel.pcss";
-@import "./views/rooms/_RoomSublist.pcss";
-@import "./views/rooms/_RoomTile.pcss";
 @import "./views/rooms/_RoomUpgradeWarningBar.pcss";
 @import "./views/rooms/_SendMessageComposer.pcss";
 @import "./views/rooms/_Stickers.pcss";