Blender Git Loki

Merge remote-tracking branch 'origin/master' into asset-browser-snap-dragging

Merge remote-tracking branch 'origin/master' into asset-browser-poselib

Attempt to fix build error on MSVC and warnings on some other compilers

On MSVC it failed with this error:
```
sourceblenderblenkernelBKE_context.h(361,20): error C2526:
'CTX_wm_asset_handle': C linkage function cannot return C++ class 'AssetHandle'
```

On Apple Clang I would get this:
```
warning: 'CTX_wm_asset_handle' has C-linkage specified, but returns incomplete
type 'struct AssetHandle' which could be incompatible with C
[-Wreturn-type-c-linkage]
struct AssetHandle CTX_wm_asset_handle(const bContext *C, bool *r_is_valid);
^
1 warning generated.
```

Just include the asset header defining the type for now, it should later on be
solved properly with a better design for `AssetHandle`.

UI: Improve walk navigation in UI List template

Add improved arrow key walk navigation in grid layout UI List templates.
Pressing up or down walks the active item to the adjacent row in that
direction, while left and right walk through the items along the columns
wrapping at the rows.

Differential Revision: https://developer.blender.org/D11063

Merge remote-tracking branch 'origin/master' into asset-browser-snap-dragging

Fix uninitialized variable use

Mistake in dc009dd6c1c1.

Merge remote-tracking branch 'origin/master' into asset-browser-poselib

Merge remote-tracking branch 'origin/master' into asset-browser-snap-dragging

T87757: Pose Library: glitch when starting to blend flipped pose

Fix a glitch when blending a pose by always starting blending at 0%.

Previously, the blend percentage was remembered between operator
invocations, causing the glitch.

Merge remote-tracking branch 'origin/master' into asset-browser-poselib

Asset Browser: also refresh asset UIlist after other blender closes

The `ASSET_OT_open_containing_blend_file` operator starts a new Blender
process, and refreshes the assets after it quits. It now also refreshes
the assets UIlist (f.e. the pose library panel in the 3D Viewport).

Merge branch 'master' into asset-browser-poselib

Avoid warning when using FileSelectEntry.id_type on a non-ID file

If the file doesn't represent an ID, the value will be `'NONE'` in
Python. Otherwise a valid ID type (e.g. `'ACTION'`, `'OBJECT'`, etc.).

Asset Browser: simple panel mix-in class for specific categories

Add a class `AssetBrowserSpecificCategoryPanel` that only shows if the
asset browser is showing a specific set of categories. This makes it
simple for the Pose Library panels to only show when the user has selected
the Animations category.

Basic snapping support for dropping objects

Uses the same snapping logic as the placement plane from the Add Object
tool, which means it matches the plane that we already draw as a
preview.

This is quite primitive at this point - you can't change options for the
snapping like the up-axis or the snapping target - but it already feels
quite great.
Another limitation is that it uses the origin of the dropped object to
place it, the bounding box should give better results in practice. This
is something we can add.

Merge remote-tracking branch 'origin/master' into asset-browser-poselib

I had to manually add a `bContext *` parameter to a
`node_geometry_add_attribute_search_button()` call to fix a compiler
error.

Merge branch 'master' into asset-browser-snap-dragging

Initial prototype for snapping plane feedback while dragging assets

Shows the same grid overlay as the Add Object tool when dragging an
asset into a 3D view. Uses the gizmo-system for that.
How visibility of gizmo-groups is managed is rather tricky, for now I
hacked things a bit to work. I have ideas to make this nicer.

Besides that, this is generally a design that I think can work in
master: Just like tools, drop-boxes can set a gizmo-group to use while
they are active. If the gizmo-group supports usage while dragging, it is
drawn.

Asset View: Activate poses when "walk" navigating the active asset

When using the arrow keys to "walk" the active item in the asset view, call the
activate operator which applies the pose asset. This is useful for animators to
easily go through poses on the search for an appropriate one.

Cleanup: Slightly correct comment from previous commit