refactor: improve thinking logic

refactor(sdk/auth): rename manager.go to conductor.go

Robust change detection: replaced string concat with struct-based compare in hasModelMappingsChanged; removed boolTo01.

feat: regex support for model-mappings

feat(amp): enhance model mapping and Gemini thinking configuration

refactor(amp): consolidate and simplify model mapping debug logs

feat(amp): add model mapping support for routing unavailable models to alternatives