recv: drop wait_seconds from the MCP tool, always an immediate peek

docs/turn-loop/mcp.md

@@ -23,7 +23,7 @@ preset (`AGENT_DEFAULT`) includes `messaging`, `meta`, `inbox`, and
 ## Core tools (always available)
 
 **Messaging** (`messaging` group): `send(to, body, in_reply_to?)`,
-`recv(wait_seconds?, max?)`, `ask(question, options?, multi?,
+`recv(max?)`, `ask(question, options?, multi?,
 ttl_seconds?, to?)`, `answer(id, answer)`, `ack_until(up_to)`.
 
 - `send` — message a peer (logical name) or the operator
@@ -36,11 +36,10 @@ ttl_seconds?, to?)`, `answer(id, answer)`, `ack_until(up_to)`.
   `[ "operator" ]` to restrict a sub-agent to operator messages only
   (the topology parent is always reachable regardless of this list —
   that carve-out is structural, keyed on parent relationship, not name).
-- `recv` — drain inbox. Without `wait_seconds` (or `0`) returns
-  immediately. Positive value parks the turn up to that many seconds
-  (cap 180) — incoming messages wake instantly. `max` (default 1, cap
-  5) drains up to N rows; `wait_seconds` applies to the first, then
-  drains up to `max` total. Each returned row is prefixed with
+- `recv` — drain inbox. Always an immediate peek, never blocks (#2814
+  — dropped the `wait_seconds` long-poll param entirely; nobody had a
+  use case for it that wasn't already better served by ending the
+  turn). `max` (default 1, cap 5) drains up to N rows. Each returned row is prefixed with
   `[msg #<id>]` (broker row id; note the highest id seen, then pass
   it to `ack_until` to bulk-triage the batch). **Graceful shutdown**: when the harness
   receives a stop signal, the inbox becomes fenced and `recv` returns an