- Kept queued resolve handlers pending when a downgraded forced tool choice completes without invoking the requested tool.
- Covered the skipped-tool and invoked-tool queue paths in tool-choice queue tests.
Fixes#2546
- Added `/force` slash command and `ToolChoiceQueue` system for managing tool-choice directives with lifecycle callbacks and requeue semantics.
- Added `setForcedToolChoice()`, `peekQueueInvoker()`, `buildToolChoice()`, `steer()`, and `getToolChoiceQueue()` methods to AgentSession and ToolSession APIs.
- Refactored tool-choice override mechanism from simple override to queue-based system with generator directives, lifecycle callbacks, and requeue preservation.
- Removed `PendingActionStore` class and replaced with `ToolChoiceQueue`; updated `ResolveTool` and custom tool loader to use queue invokers.
- Fixed tool-choice queue cleanup on agent loop abort and requeue semantics to preserve callbacks across abort cycles.