Folds the legacy services/settingsService SQL into the Nest SettingsService
(byte-identical statements; BEGIN/COMMIT blocks become db.transaction()).
AdminService and ShareService inject it; llm-config.resolver becomes the
injectable LlmConfigResolver (SettingsService + DatabaseService), injected by
LlmParseService and PluginHostDepsFactory. No MCP surface, no bridge.
Whole-file commit, so this also carries the post-migration quirk fixes that
live in the same files: null serializes as '' (a stored "null" leaked out of
getDecryptedUserSetting as the literal string), bulk upserts skip the masked
sentinel (mirroring the single-upsert no-op) and return the written count.
Unit suite moved to tests/unit/nest with SET-SVC-001..026 preserved,
027..030 pin the fixes; settings/admin e2e converted to DI-native.
jubnl