hermes - 💡(How to fix) Fix [Feature] Print delegated task model at start (CLI + Discord)

Problem

When a delegated task starts, the user has no visibility into which model was selected. This is critical for:

• Cost analysis (tracking per-task model spend)
• Quality monitoring (which model produced what output)
• Debugging (validating model selection logic)

Current Behavior

Task starts silently. Model selection is invisible to user.

Example (CLI): ``` [1] ├─ 🔀 Generate marketing copy ```

Example (Discord): No message sent when task delegates.

Desired Behavior

CLI

``` [1] ├─ 🔀 Generate marketing copy [model: kimi-k2.6:cloud] ```

Discord

``` 🚀 Task delegated • Model: `kimi-k2.6:cloud` • Goal: Generate marketing copy ```

Scope

START PHASE ONLY — Print model when task delegates (not on completion).

Implementation Plan

Phase 1: CLI Display (High Priority)

• Enhance spinner display in `_build_child_progress_callback()` @ line 760
• Add model label to `subagent.start` event rendering
• Effort: 30 min, 10 LOC

Phase 2: Discord Delivery (Medium Priority)

• Emit send_message call on task start
• Integrate with progress callback at line 1508
• Effort: 1.5 hours, 40 LOC

Phase 3: Testing (Required)

• Unit tests: progress callback receives model
• Integration test: model visible in CLI output
• Effort: 30 min, 25 LOC

Files to Modify

1. `tools/delegate_tool.py` (~line 760, ~1506-1510)
2. `tests/tools/test_delegate.py` (test cases)
3. `send_message_tool.py` (optional integration)

Backwards Compatibility

✅ No breaking changes. Purely additive.

References

• Research Report: /tmp/MODEL_VISIBILITY_TWO_PHASE_REPORT.md
• Related: #34489 (per-task model override)

Acceptance Criteria

• CLI spinner shows model in subagent.start event
• Discord message sent when task delegates (if running on Discord)
• All existing tests pass
• 3+ new unit tests added
• No breaking changes

Points: 2