Replace 30+ repetitive setter method bodies with four generic private
helpers: setGlobalSetting, setScopedSetting, setNestedGlobalSetting,
and setProjectSetting. Each setter method retains its original public
signature and behavior — only the internal implementation is consolidated.
Methods with custom logic (setEditorPaddingX, setAutocompleteMaxVisible,
setSearchExcludeDirs, setFallbackChain, removeFallbackChain,
setDefaultModelAndProvider) are left unchanged or minimally adapted.
Net reduction: 79 lines (164 deleted, 85 added).
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