[Bug]: Native tool-call assistant text is dropped from draft updates

[whtiehack]

Affected component

channel

Severity

S2 - degraded behavior

Current behavior

When a provider uses native tool calling and returns both assistant text and structured tool_calls, draft-capable channel updates only receive the tool-progress message. The assistant explanation text is dropped before it reaches on_delta.

On current master, resolve_display_text() returns parsed_text for any turn that contains tool calls. Native tool-call turns often have empty parsed_text, so the assistant's separate text payload is lost.

Expected behavior

For native tool-call turns, if there is no parsed inline text but the provider returned assistant text, that text should be preserved and relayed through on_delta before tool execution starts.

Steps to reproduce

1. Check out the latest master branch. I reproduced this on commit 65cb4fe0.
2. Configure Telegram with draft streaming enabled.
3. Trigger a native tool-call response where the provider returns assistant text alongside structured tool calls, for example:

{
  "text": "Task started. Waiting 30 seconds before checking status.",
  "tool_calls": [
    {
      "id": "call_wait",
      "name": "count_tool",
      "arguments": "{\"value\":\"A\"}"
    }
  ]
}

4. Observe the streamed draft output in Telegram.
5. The tool-progress line is emitted, but the assistant text above is missing.

Impact

Affected users: Telegram users with streaming drafts enabled, and any other draft-capable channel consuming on_delta
Frequency: whenever the provider returns separate assistant text plus structured tool_calls
Consequence: users see tool execution progress without the model's accompanying explanation or status message

Logs / stack traces

Observed symptom in streamed output:

💬 Got 1 tool call(s)
⏳ count_tool: {"value":"A"}
✅ count_tool

Expected streamed output should also include the assistant text before tool execution, for example:

Task started. Waiting 30 seconds before checking status.
💬 Got 1 tool call(s)
⏳ count_tool: {"value":"A"}
✅ count_tool

ZeroClaw version

master @ 65cb4fe0

Rust version

rustc 1.93.1 (01f6ddf75 2026-02-11)

Operating system

macOS 12.7.4

Regression?

Unknown

Pre-flight checks

• I reproduced this on the latest master branch or latest release.
• I redacted secrets, tokens, and personal data from all submitted content.