simplify（简化）

Review changes in the current branch, or in the state the user specifies. Apply these criteria without changing behavior:

1. Names: Shorten verbose names while keeping them clear. Prefer human-readable concepts (baseline) over compound phrases that are more mechanical / academic (lastObservedDiskContent).
2. Combine related concepts: If two types, functions, or constants overlap significantly, merge them. The fewer distinct concepts a reader must hold in their head, the better. *Example: two union types sharing 3 of 4 values → one type with shorter value names.*
3. Derivability: If a value can be computed from other values already in scope, don't pass or store it separately. Removing derivable state often simplifies signatures, types, and control flow in one move. *Example: an isDirty parameter that's always derived from computing editorContent!== baseline can be dropped.*
4. Scope: Only touch code in the specified scope. Validate your work does not break existing functionality.