[matt-edmondson]

Note(string) threw ArgumentException for a null or whitespace key. Note(NoteName) trimmed the same input to "" and built an empty note, because ValidateKey only checks keys longer than one character. That empty note caused three problems:

• A chord holding it displayed as Ctrl+.
• The chord could be bound and executed.
• The binding was dropped on the next load, because the stored "" can't be read back into a note.

Note(NoteName) now throws the same ArgumentException("Key cannot be null or whitespace", nameof(key)) as Note(string) before it normalizes, so both constructors behave as their XML docs say. A host that maps an unmapped framework key to a blank name now gets an error at the point it builds the note. Before, the binding disappeared silently on restart.

Tests

• New BlankNoteNameTests:
  • new Note(NoteName.Create(x)) throws ArgumentException with ParamName == "key" for "", " " and "\t".
  • A matching set pins the string constructor to the same exception and message.
• The existing NoteJsonSerializationTests.Deserialize_BlankKey_ThrowsJsonException already covers deserializing a blank key, so this PR doesn't duplicate it.
• With the fix reverted, the three NoteName rows fail. With the fix in, the full suite passes (334/334).
• I checked locally that this branch merges cleanly with every other open branch in the repo (Merge and write stored commands under one lock, so concurrent saves keep each other's commands [patch] #204, Fold browser, Silk.NET, ImGui, GLFW and macOS modifier names into Ctrl, Alt, Shift and Meta [patch] #209, Use the registered IKeybindingService in KeybindingManager [patch] #210, Merge a stored profile into one created before InitializeAsync instead of dropping it [patch] #211).

Fixes #212

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Generated by Claude Code

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

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