feat(messaging): expose action='unreact' in send_message + react dispatch tests

Follow-up for salvaged PR #44486: the adapter shipped remove_reaction but
the tool only exposed 'react'. Generalize _handle_react(remove=) and add
tool-level dispatch tests for react/unreact (missing from the original PR).

tests/tools/test_send_message_react.py

@@ -0,0 +1,97 @@
+"""Tests for send_message action='react'/'unreact' dispatch.
+
+Kept separate from ``test_send_message_tool.py`` because that module skips
+wholesale when optional Telegram dependencies are not installed.
+"""
+
+import json
+from types import SimpleNamespace
+from unittest.mock import patch
+
+import tools.send_message_tool as smt
+
+
+class _FakePhotonAdapter:
+    """Adapter exposing add_reaction/remove_reaction coroutines."""
+
+    def __init__(self):
+        self.calls = []
+
+    async def add_reaction(self, chat_id, emoji, message_id=None):
+        self.calls.append(("add", chat_id, emoji, message_id))
+        return {"success": True, "emoji": emoji}
+
+    async def remove_reaction(self, chat_id, message_id=None):
+        self.calls.append(("remove", chat_id, message_id))
+        return {"success": True}
+
+
+class _NoReactionAdapter:
+    """Adapter with no reaction support at all."""
+
+
+def _runner_with(adapter):
+    from gateway.config import Platform
+
+    return SimpleNamespace(adapters={Platform("photon"): adapter})
+
+
+def _call(args):
+    return json.loads(smt.send_message_tool(args))
+
+
+def test_react_dispatches_to_add_reaction():
+    adapter = _FakePhotonAdapter()
+    with patch("gateway.run._gateway_runner_ref", lambda: _runner_with(adapter)):
+        result = _call(
+            {"action": "react", "target": "photon:+15551234567", "emoji": "❤️"}
+        )
+    assert result["success"] is True
+    assert adapter.calls == [("add", "+15551234567", "❤️", None)]
+
+
+def test_unreact_dispatches_to_remove_reaction():
+    adapter = _FakePhotonAdapter()
+    with patch("gateway.run._gateway_runner_ref", lambda: _runner_with(adapter)):
+        result = _call(
+            {
+                "action": "unreact",
+                "target": "photon:+15551234567",
+                "message_id": "msg-9",
+            }
+        )
+    assert result["success"] is True
+    assert adapter.calls == [("remove", "+15551234567", "msg-9")]
+
+
+def test_react_requires_emoji():
+    result = _call({"action": "react", "target": "photon:+15551234567"})
+    assert result.get("success") is not True
+    assert "emoji" in json.dumps(result)
+
+
+def test_unreact_does_not_require_emoji():
+    adapter = _FakePhotonAdapter()
+    with patch("gateway.run._gateway_runner_ref", lambda: _runner_with(adapter)):
+        result = _call({"action": "unreact", "target": "photon:+15551234567"})
+    assert result["success"] is True
+    assert adapter.calls == [("remove", "+15551234567", None)]
+
+
+def test_react_unsupported_platform_adapter():
+    adapter = _NoReactionAdapter()
+    with patch("gateway.run._gateway_runner_ref", lambda: _runner_with(adapter)):
+        result = _call(
+            {"action": "react", "target": "photon:+15551234567", "emoji": "👍"}
+        )
+    assert result.get("success") is not True
+    assert "does not support" in json.dumps(result)
+
+
+def test_react_without_live_gateway():
+    with patch("gateway.run._gateway_runner_ref", lambda: None):
+        result = _call(
+            {"action": "react", "target": "photon:+15551234567", "emoji": "👍"}
+        )
+    assert result.get("success") is not True
+    assert "live" in json.dumps(result)