Modifier names from browsers, Silk.NET, ImGui and GLFW aren't canonicalized: ControlLeft+C never equals Ctrl+C and displays as C+CONTROLLEFT #205

What's wrong

Note.CanonicalizeKey (Keybinding/Models/MusicalTypes.cs:74-83) folds the WinForms, WPF and ConsoleKey modifier spellings into CTRL, ALT, SHIFT and META. Several other common spellings are not folded:

• Browser KeyboardEvent.code: ControlLeft/ControlRight, ShiftLeft, AltLeft, MetaLeft, OSLeft
• Silk.NET Key: ControlLeft, ShiftLeft, AltLeft, SuperLeft
• ImGuiKey: LeftSuper (LeftCtrl is already handled)
• GLFW: LEFT_CONTROL, LEFT_SHIFT, LEFT_ALT, LEFT_SUPER
• macOS-style LeftCommand

Each of these is treated as an ordinary key. As a result:

• the chord never equals the canonical one;
• IsModifierNote is false;
• the modifier sorts after the main key when the chord is displayed.

This matters for the org's own stack. ImGuiApp is built on Silk.NET and ImGui, so a binding captured from a Silk.NET key event cannot match one written as Ctrl+C. #166 and #198 widened the alias table, but they did not cover these spellings.

Reproduction (HEAD b035bdb)

foreach (string s in new[] { "ControlLeft+C","ControlRight+C","LeftSuper+C","SuperLeft+C","MetaLeft+C","ShiftLeft+C","AltLeft+C","OSLeft+C","LEFT_CONTROL+C","LeftCommand+C" })
{
    Chord c = Chord.Parse(s);
    bool eq = c == Chord.Parse("Ctrl+C") || c == Chord.Parse("Meta+C") || c == Chord.Parse("Shift+C") || c == Chord.Parse("Alt+C");
    Console.WriteLine($"{s} -> '{c}' equals canonical: {eq}");
}

ControlLeft+C  -> 'C+CONTROLLEFT'  equals canonical: False
ControlRight+C -> 'C+CONTROLRIGHT' equals canonical: False
LeftSuper+C    -> 'C+LEFTSUPER'    equals canonical: False
SuperLeft+C    -> 'C+SUPERLEFT'    equals canonical: False
MetaLeft+C     -> 'C+METALEFT'     equals canonical: False
ShiftLeft+C    -> 'C+SHIFTLEFT'    equals canonical: False
AltLeft+C      -> 'ALTLEFT+C'      equals canonical: False
OSLeft+C       -> 'C+OSLEFT'       equals canonical: False
LEFT_CONTROL+C -> 'C+LEFT_CONTROL' equals canonical: False
LeftCommand+C  -> 'C+LEFTCOMMAND'  equals canonical: False

Expected: each spelling equals the canonical chord and displays as Ctrl+C, Meta+C, Shift+C or Alt+C.

Suggested fix / acceptance criteria

• Extend the switch with these names:
  • CONTROLLEFT/CONTROLRIGHT
  • ALTLEFT/ALTRIGHT
  • SHIFTLEFT/SHIFTRIGHT
  • METALEFT/METARIGHT
  • SUPERLEFT/SUPERRIGHT
  • LEFTSUPER/RIGHTSUPER
  • OSLEFT/OSRIGHT
  • LEFTCOMMAND/RIGHTCOMMAND
  • the GLFW forms LEFT_CONTROL, LEFT_SHIFT, LEFT_ALT, LEFT_SUPER and their RIGHT_* counterparts
• Add a row to KeyAliasEquivalenceTests for each spelling.