ask: rename ask_operator → ask + optional 'to' for agent-to-agent Q&A

docs/approvals.md

@@ -248,16 +248,25 @@ package legitimacy, cheaper alternative, blast radius) before
 committing and calling `request_apply_commit`.
 
 For ambiguous cases or anything that needs human signal, the
-manager calls `ask_operator(question, options?, multi?,
-ttl_seconds?)` — queues the question on the dashboard and returns
-the id immediately. The operator's answer arrives later as
-`HelperEvent::OperatorAnswered` in the manager inbox. Storage is
-`hive-c0re::operator_questions` (sqlite); the answer flow is:
+manager calls `ask(question, options?, multi?, ttl_seconds?, to?)` —
+queues the question and returns the id immediately. When `to` is
+omitted (or `"operator"`) the question shows up on the dashboard;
+when `to` is a sub-agent's name, the recipient receives a
+`HelperEvent::QuestionAsked` and answers via their own `answer`
+tool. Either way the answer arrives back as
+`HelperEvent::QuestionAnswered { id, question, answer, answerer }`
+in the asker's inbox. Storage is `hive-c0re::operator_questions`
+(sqlite) — same table, with a nullable `target` column
+(NULL = operator). Dispatch goes through
+`hive-c0re/src/questions.rs::{handle_ask, handle_answer}` so both
+the agent + manager surfaces stay aligned. The answer flow is:
 
 ```
-POST /answer-question/{id}
-  → OperatorQuestions::answer
-  → notify_manager(OperatorAnswered { id, question, answer })
+POST /answer-question/{id}                       agent: Answer { id, answer }
+  → OperatorQuestions::answer(_, _, "operator")    → questions::handle_answer
+  → notify_agent(asker, QuestionAnswered {         → OperatorQuestions::answer(_, _, agent)
+       answerer: "operator", ... })                → notify_agent(asker, QuestionAnswered {
+                                                       answerer: agent, ... })
 ```
 
 Two more paths resolve a pending question with a sentinel answer:
@@ -301,9 +310,14 @@ regular claude turn so the manager can react. Variants
 - `NeedsUpdate { agent }` — sub-agent's recorded flake rev is
   stale. Manager calls `update(name)` to rebuild — idempotent,
   no approval required.
-- `OperatorAnswered { id, question, answer }` — dashboard
-  `/answer-question/{id}` after the operator submits the answer
-  form.
+- `QuestionAnswered { id, question, answer, answerer }` —
+  dashboard `/answer-question/{id}` (answerer = `"operator"`),
+  peer `Answer` request (answerer = agent name), or ttl watchdog
+  expiry (answerer = `"ttl-watchdog"`, answer = `"[expired]"`).
+- `QuestionAsked { id, asker, question, options, multi }` —
+  fired when an agent calls `Ask { to: Some(<this-agent>), ... }`.
+  The recipient responds via `Answer { id, answer }` and the
+  asker sees the matching `QuestionAnswered`.
 
 To add a new event: new `HelperEvent` variant + call sites + update
 `prompts/manager.md` so the manager knows the new shape.