Use Home credential options as authoritative model capability
configuration for compat handling and prompt cache behavior.
Expose quota provider operations through the public plugin host API.
- Attach resolved execution model info during execution and token counting even when restoring execution models
- Propagate configuration update support to resolved Home dispatch model info
- Track modifications to configuration updates across plugin normalizers in the translation pipeline
- Mark configuration update support for eligible Codex models in the registry
- Replaced instances of `thinking.ApplyThinking` with `helps.ApplyRequestThinking` across all executors for consistency.
- Updated `applyGeminiInteractionsThinking` to accept `cliproxyexecutor.Request` and `Options`.
- Centralized logic for request thinking application to `helps` package for improved maintainability.
Closes: #4618
