Add `piker.ui.qt` as a `PyQt6` shim module

For the future, like if we ever get a `PyQt7` (or wtv else..), add
a module which allows changing Qt binding lib imports from one spot for
all other `.ui` submodules. In some sense this is like a shoddier, less
dynamic version of how `pyqtgraph.Qt.__init__.py` supports multiple
libs; it might actually make sense eventually to instead import from
their shim layer instead?

Included is a draft attempt at exposing a bunch of enums which under
custom names:
- while the specific grouping of values seem to always stay consistent,
  the root enum's seem to almost always get moved around in the `PyQtX`
  module namespace.
- changing groupings and/or each top level enum's ns location can more
  simply be changed/re-orged from one spot.
- allows `.ui` consumer code to use a name more relevant to `piker`'s
  usage of wtv UI component is being configured.

piker/ui/qt.py

@@ -0,0 +1,104 @@
+# piker: trading gear for hackers
+# Copyright (C) Tyler Goodlet (in stewardship for pikers)
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+'''
+Qt UI framework version shimming.
+
+Allow importing sub-pkgs from this module instead of worrying about
+major version specifics, any enum moves or component renames.
+
+Code in `piker.ui.*` should always explicitlyimport directly from
+this module like `from piker.ui.qt import ( ..`
+
+'''
+from enum import EnumType
+
+from PyQt6 import (
+    QtCore,
+    QtGui,
+    QtWidgets,
+)
+from PyQt6.QtCore import (
+    Qt,
+    QCoreApplication,
+    QLineF,
+    QRectF,
+    # NOTE: for enums use the `.Type`  subattr-space
+    QEvent,
+    QPointF,
+    QSize,
+    QModelIndex,
+    QItemSelectionModel,
+    pyqtBoundSignal,
+    pyqtRemoveInputHook,
+)
+
+align_flag: EnumType = Qt.AlignmentFlag
+txt_flag: EnumType = Qt.TextFlag
+keys: EnumType = QEvent.Type
+scrollbar_policy: EnumType = Qt.ScrollBarPolicy
+
+# ^-NOTE-^: handy snippet to discover enums:
+# import enum
+# [attr for attr_name in dir(QFrame)
+#  if (attr := getattr(QFrame, attr_name))
+#  and isinstance(attr, enum.EnumType)]
+
+from PyQt6.QtGui import (
+    QPainter,
+    QPainterPath,
+    QIcon,
+    QPixmap,
+    QColor,
+    QTransform,
+    QStandardItem,
+    QStandardItemModel,
+    QWheelEvent,
+    QScreen,
+    QCloseEvent,
+)
+
+from PyQt6.QtWidgets import (
+    QMainWindow,
+    QApplication,
+    QLabel,
+    QStatusBar,
+    QLineEdit,
+    QHBoxLayout,
+    QVBoxLayout,
+    QFormLayout,
+    QProgressBar,
+    QSizePolicy,
+    QStyledItemDelegate,
+    QStyleOptionViewItem,
+    QComboBox,
+    QWidget,
+    QFrame,
+    QSplitter,
+    QTreeView,
+    QStyle,
+    QGraphicsItem,
+    QGraphicsPathItem,
+    # QGraphicsView,
+    QStyleOptionGraphicsItem,
+    QGraphicsScene,
+    QGraphicsSceneMouseEvent,
+    QGraphicsProxyWidget,
+)
+
+gs_keys: EnumType = QGraphicsSceneMouseEvent.Type
+size_policy: EnumType = QtWidgets.QSizePolicy.Policy
+px_cache_mode: EnumType = QGraphicsItem.CacheMode