Add Shotcut QML documentation

[ddennedy]

Adds a QDoc-generated reference for Shotcut’s QML scripting surface by annotating existing C++ QML-facing classes/models/docks with \qmltype, \qmlproperty and \qmlmethod blocks; and wiring a CMake option/target to generate HTML docs.

Changes:

• Added extensive inline QDoc for org.shotcut.qml context properties/types (Filter/Producer/Profile/Application/Settings/etc.) and key models/docks used by QML views.
• Added new QDoc structure files for org.shotcut.qml and Shotcut.Controls, plus a minimal CSS for readability.
• Added BUILD_DOCS option + docs custom target and updated build/preset/gitignore for generated output.

[Copilot]

Pull request overview

Adds a QDoc-generated reference for Shotcut’s QML scripting surface by annotating existing C++ QML-facing classes/models/docks with \qmltype/\qmlproperty/\qmlmethod blocks, and wiring a CMake option/target to generate HTML docs.

Changes:

• Added extensive inline QDoc for org.shotcut.qml context properties/types (Filter/Producer/Profile/Application/Settings/etc.) and key models/docks used by QML views.
• Added new QDoc structure files for org.shotcut.qml and Shotcut.Controls, plus a minimal CSS for readability.
• Added BUILD_DOCS option + docs custom target and updated build/preset/gitignore for generated output.

Reviewed changes

Copilot reviewed 26 out of 27 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
src/settings.cpp	Adds QDoc for the settings context property and selected settings properties.
src/qmltypes/qmlview.cpp	Documents the view context property and its geometry helper.
src/qmltypes/qmlrichtext.cpp	Documents the RichText helper API used by the Text: Rich filter UI.
src/qmltypes/qmlprofile.cpp	Documents the profile context property (project video mode info).
src/qmltypes/qmlproducer.cpp	Documents the producer context property (clip info for filter panels).
src/qmltypes/qmlmetadata.cpp	Documents metadata and keyframes metadata descriptor types.
src/qmltypes/qmlfilter.cpp	Documents the main filter scripting interface for filter panels/VUIs.
src/qmltypes/qmlfile.cpp	Documents a QML-friendly file URL wrapper with file watching support.
src/qmltypes/qmlextension.cpp	Documents extension package types (e.g., Whisper downloads).
src/qmltypes/qmlapplication.cpp	Documents the application context property utilities and signals.
src/models/subtitlesmodel.cpp	Documents subtitle model/selection model QML-facing API.
src/models/multitrackmodel.cpp	Documents timeline model roles/signals and key QML methods.
src/models/motiontrackermodel.cpp	Documents the motion tracker list model used in Filters panels.
src/models/markersmodel.cpp	Documents the timeline markers model API and roles.
src/models/keyframesmodel.cpp	Documents the keyframes parameter/keyframe model API.
src/models/attachedfiltersmodel.cpp	Documents the attached-filters list model used by the Filters dock.
src/docks/timelinedock.cpp	Documents the Timeline dock controller context property API.
src/docks/keyframesdock.cpp	Documents the Keyframes dock controller context property API.
docs/src/shotcut-controls.qdoc	Introduces the Shotcut.Controls QML module doc page.
docs/src/shotcut-controls-types.qdoc	Adds type-level docs for native controls/dialogs exposed to QML.
docs/src/org-shotcut-qml.qdoc	Introduces the org.shotcut.qml module overview page.
docs/src/index.qdoc	Adds the landing page and overview tables for context properties/modules.
docs/shotcut.css	Adds a custom stylesheet for generated HTML docs readability.
docs/qml-api.qdocconf	Adds QDoc configuration listing sources and output settings.
CMakePresets.json	Enables docs generation via cache variable in a debug preset.
CMakeLists.txt	Adds BUILD_DOCS option and a docs custom target invoking QDoc.
.gitignore	Ignores generated docs output directory and a workspace file.