Web UI sends tool args instead of confirmation payload, crashing the agent

[vietnamesekid]

Bug

I was following the official docs at https://adk.dev/tools-custom/confirmation/#confirmation-definition
to implement a custom confirmation flow using tool_context.request_confirmation(payload={...}).

After implementing it, I noticed that when submitting the confirmation form, the agent
receives the tool's original args instead of the payload schema I specified, causing a
KeyError crash.

Reproduce

def request_time_off(days: int, tool_context: ToolContext):
    tool_confirmation = tool_context.tool_confirmation
    if not tool_confirmation:
        tool_context.request_confirmation(
            payload={'approved_days': days},
        )
        return {'status': 'pending'}

    payload = tool_confirmation.payload or {}
    approved_days = payload['approved_days']  # KeyError here

1. Run adk web
2. Trigger request_time_off with days=4
3. Submit the confirmation form
4. Agent crashes with KeyError: 'approved_days' because the submitted payload is { "days": 4 } instead of { "approved_days": 4 }

Root Cause

adk-python (functions.py) correctly sends both originalFunctionCall and
toolConfirmation (including payload) in the event. The bug is in
long-running-response.ts where initForm() initializes confirmationModel.payload
from originalFunctionCall.args instead of toolConfirmation.payload. Since onSend()
reads confirmationModel.payload to build the submit request, the wrong payload gets sent.

Proposed Fix

// long-running-response.ts
this.confirmationModel.payload = JSON.stringify(
  this.functionCall.args?.toolConfirmation?.payload ??
  this.functionCall.args?.originalFunctionCall?.args ??
  {}, null, 2
);