MS-256/use negative temp IDs to prevent unsaved notes collision
New notes were assigned id: 0, causing all unsaved notes to share the same ID. This made updateNote match all of them simultaneously when editing any single one.
- Add tempIdCounter ref (starts at -1, decrements per new note)
- Use tempIdCounter.current-- as id in addNote so each unsaved note gets a unique negative ID that never collides with backend IDs
- Guard deleteNote call in removeNote with id > 0 to skip API calls for notes that were never persisted
- Remove "Editeur de rôles" navigation entry from dashboard config
Closes MS-256