Permission mode now tracked at the time of the original request

What

• A new permissionModeAtRequest field is now threaded through tool-use handling, capturing the concrete permission mode (default, acceptEdits, dontAsk, or bubble) that an "auto" mode resolves to at the moment a tool request is made; plan and bypassPermissions both resolve to default. This replaces an earlier, simpler mode field.
• When replying to a tool_use request, Claude Code now restores the permission mode that request was originally made under, but only when the effective mode is "arbiter" and a gate check passes.
• A new telemetry event, tengu_auto_mode_decided_as_requested_mode, fires when auto-mode's eventual decision matches the mode that was originally requested, recording the tool name, whether it's an MCP tool, and the requested mode.

Why

This keeps permission decisions consistent with the mode that was actually in effect when a tool request was made, and provides telemetry to measure how often auto-mode's decision simply confirms the original request.