feat: Add layout debugging/inspecting tool (#14919)

* Add wxInspector dep

* Initial intergration of wxInspector

* docs: add wxInspector plugins design spec

Design spec for two wxInspector plugins (DPIAware + CustomWidgets) that expose
OrcaSlicer's custom control properties in the inspector property grid.

Covers: DPIAware scale-factor properties, Button, CheckBox, TextInput,
SwitchButton, ProgressBar, Label, and LabeledStaticBox.

* docs: add wxInspector plugins implementation plan

6-task plan covering: source changes to existing widget headers,
DPIAwarePlugin, CustomWidgetsPlugin, registration helper,
MainFrame/CMake wiring, and build verification.

* feat: add getters/setters for wxInspector plugin access

Add minimal public accessors to DPIAware (set_scale_factor,
set_prev_scale_factor, set_em_unit, force_rescale), Button
(GetStyle, GetType, IsSelected), CheckBox (IsHalfChecked),
TextInput (GetCornerRadius), and LabeledStaticBox
(GetCornerRadius, GetBorderWidth, GetBorderColor, GetScale).

* feat: add wxInspector plugin registration helper

Add RegisterOrcaInspectorPlugins() inline function that creates
and registers the DPIAwarePlugin and CustomWidgetsPlugin as
static instances (matching wxInspector's built-in pattern).

* feat: add DPIAware wxInspector plugin

Exposes DPI scaling properties (scale_factor, prev_scale_factor,
em_unit, normal_font, force_rescale) on DPIFrame and DPIDialog
widgets. Uses dynamic_cast for detection and a template helper
to capture the correct static type for lambda accessors.

* feat: add OrcaCustomWidgets wxInspector plugin

Exposes Orca-specific properties on 7 widget types:
- Button: Style, Type, Selected
- CheckBox: Half Checked
- TextInput: Label, Text Value, Corner Radius
- SwitchButton: Value
- ProgressBar: Proportion, Show Number
- Label: Is Hyperlink, Font Point Size
- LabeledStaticBox: Corner Radius, Border Width, Border Color, Scale

Each widget type uses dynamic_cast for safe detection.

* feat: wire wxInspector plugins into MainFrame and build

Call RegisterOrcaInspectorPlugins() in MainFrame constructor after
SetupInspectorAccelerator(). Add all 5 plugin source files to
SLIC3R_GUI_SOURCES in CMakeLists.txt.

* fix: move plugin registration to GUI_App::on_init_inner

Register plugins once in app init rather than in MainFrame
constructor, which may be recreated during the application
lifetime.

* fix: include plugin headers in Registration.hpp for complete types

Static locals require complete type. Include DPIAwarePlugin.hpp and
CustomWidgetsPlugin.hpp instead of forward-declaring. Also remove
unused include from MainFrame.cpp (registration moved to GUI_App).

* fix: qualify DPIFrame/DPIDialog with Slic3r::GUI namespace

* Make DPIDialog inspectable. For other dialogs, we will add them if necessary later.

* docs: add spec for moving wxInspectable into DPIAware template

Move wxInspector::wxInspectable base class from DPIDialog and MainFrame
into the common DPIAware<P> template, making all DPIAware widgets
automatically visible in the inspector tree.

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

* docs: add implementation plan for moving wxInspectable into DPIAware

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

* docs: update spec/plan — move SetupInspectorAccelerator into DPIAware too

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

* refactor: move wxInspectable and SetupInspectorAccelerator into DPIAware

DPIAware<P> now inherits wxInspector::wxInspectable and calls
SetupInspectorAccelerator in its constructor, making all DPIAware
widgets automatically appear in the inspector tree with the
Ctrl+Shift+I shortcut. DPIDialog now uses 'using' to inherit the
constructor. Remove redundant wxInspectable inheritance and
SetupInspectorAccelerator calls from DPIDialog and MainFrame.

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

* fix: use LB_HYPERLINK constant instead of magic number 0x0020

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

* Clean up

* Fix Linux build

* Don't build wxInspector sample

* Use shallow clone

* Try fix flatpak build

* Attempt to fix build again

* Fix build failure caused by https://github.com/wxWidgets/wxWidgets/commit/436c16135ec7ddf580f44624bf74c592aae43b66

* wxWidgets build only download required submodules

* This should fix build on Windows on ARM

* Enable PIC

* Disable layout inspector by default for public release

* Use wxInspector 1.0.0 release

---------

Co-authored-by: Claude <noreply@anthropic.com>

deps/wxInspector/wxInspector.cmake

@@ -0,0 +1,13 @@
+orcaslicer_add_cmake_project(
+    wxInspector
+    URL https://github.com/Noisyfox/wxInspector/archive/refs/tags/v1.0.0.zip
+    URL_HASH SHA256=0ba163956f2d468b19a91b96c5aba66ee9610843ea41dda628ea44cdafde7db7
+    DEPENDS ${WXWIDGETS_PKG}
+    CMAKE_ARGS
+        -DCMAKE_CXX_FLAGS="-DwxDEBUG_LEVEL=0"
+        -DCMAKE_POSITION_INDEPENDENT_CODE=ON
+)
+
+if (MSVC)
+    add_debug_dep(dep_wxInspector)
+endif ()