fix(main-editor): report the tune editor to the sub-editor callbacks

[hm21]

Description

Problem. onOpenSubEditor, onStartCloseSubEditor and onEndCloseSubEditor reported the tune editor as SubEditor.unknown. openTuneEditor pushes the editor inside a HeroMode, so openPage's page is TuneEditor check never matched. The T is ... checks next to the page checks could not help either: T is a type argument, so T is TuneAdjustmentMatrix compares a Type object with a class and is always false. An app that reacts to the opened sub-editor, for example to reset the canvas zoom or show its own tune controls, had to special-case the tune editor at every call site.

Changes.

• openPage looks through a HeroMode before checking the editor type.
• The always-false T is ... checks are removed; the detection now relies on the page type alone, which is what already matched for every other editor.

Tests. In main_editor_test.dart, opening the tune editor reports [SubEditor.tune] to onOpenSubEditor. Before the fix it reported [SubEditor.unknown].

Verification.

• flutter test (920) and flutter analyze pass on Flutter 3.47.2.
• Galaxy S26, in an app that resets its canvas zoom from onOpenSubEditor for the paint, filter and tune editors: before, opening the tune editor from a zoomed canvas left the zoom in place; after, the canvas resets like it does for the other two.

Version bumped to 14.10.2 with a changelog entry.

Related Issue: none

Type of Change

• ✨ New feature (non-breaking change which adds functionality)
• 🛠️ Bug fix (non-breaking change which fixes an issue)
• ❌ Breaking change (fix or feature that would cause existing functionality to change)
• 🧹 Code refactor
• ✅ Build configuration change
• 📝 Documentation
• 🗑️ Chore