feat(tools): per-call approval for action tools

3-way action_tool_policy (off/ask/allow). In "ask", the chat stream stays
open and the tool loop awaits approval: emits event:tool_request, the UI
shows Approve/Deny, POST /chat/approve resumes the same stream. Declined
actions return a denied result; a timeout denies.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/test_tools.py

@@ -41,6 +41,56 @@ def test_action_tools_registered():
     assert names == ["web_search", "remember"]
 
 
+class _ActionManager:
+    """Returns a `remember` (action) tool_call once, then plain content."""
+    def __init__(self):
+        self.n = 0
+
+    async def chat(self, **_):
+        self.n += 1
+        if self.n == 1:
+            return {"role": "assistant",
+                    "tool_calls": [{"function": {"name": "remember", "arguments": {"text": "x"}}}]}
+        return {"role": "assistant", "content": "done"}
+
+
+def _drive_with_decision(decision, monkeypatch):
+    from synapse import chat as chatmod
+
+    async def fake_dispatch(name, args):
+        return "saved-ok"
+    monkeypatch.setattr(tools, "dispatch", fake_dispatch)
+
+    async def run():
+        messages = [{"role": "user", "content": "remember x"}]
+        gen = chatmod._run_tool_loop(_ActionManager(), messages, "m", [{}], None, None,
+                                     conversation_id="conv", policy="ask")
+        statuses = []
+        async for s in gen:
+            statuses.append(s)
+            if s.startswith("__approve__"):
+                w = chatmod.pending_approvals["conv"]
+                w["decisions"] = {"remember": decision}
+                w["event"].set()
+        return statuses, messages
+
+    return asyncio.run(run())
+
+
+def test_ask_policy_pauses_then_runs_on_approve(monkeypatch):
+    statuses, messages = _drive_with_decision(True, monkeypatch)
+    assert any(s.startswith("__approve__") for s in statuses)   # paused for approval
+    assert "__status__remember" in statuses                     # approved -> ran
+    assert any(m["role"] == "tool" and "saved-ok" in m["content"] for m in messages)
+
+
+def test_ask_policy_skips_on_deny(monkeypatch):
+    statuses, messages = _drive_with_decision(False, monkeypatch)
+    assert any(s.startswith("__approve__") for s in statuses)
+    assert "__status__remember" not in statuses                 # denied -> never ran
+    assert any(m["role"] == "tool" and "declined" in m["content"] for m in messages)
+
+
 def test_action_tools_gated_by_consent():
     allow = ["search_memory", "web_search", "remember", "fetch_url"]
     on = [s["function"]["name"] for s in tools.schemas_for(allow, allow_actions=True)]