ask_operator: multi-select + free-text fallback

ask_operator now accepts a multi: bool. when true and options is
non-empty, the dashboard renders the choices as checkboxes — operator
picks any subset, answer comes back as a ', '-joined string. when
false (default), options are radio buttons.

independent of multi, a free-text input ('or type your own…') is
always rendered alongside options so the operator is never trapped
by an incomplete list. submit merges checked options + free text into
the single 'answer' field.

schema migration: operator_questions grows a multi INTEGER column
with a one-shot ALTER TABLE on open. backward compatible — old rows
default to 0 (not multi).

prompt + mcp tool description updated; existing dashboard css for
.qform was rewritten around the new vertical layout.

hive-sh4re/src/lib.rs

@@ -289,13 +289,22 @@ pub enum ManagerRequest {
         agent: String,
         commit_ref: String,
     },
-    /// Ask the operator a question. The host-side handler blocks until the
-    /// operator answers via the dashboard; the answer is then returned as the
-    /// response. `options` is advisory: an empty list means free-text.
+    /// Ask the operator a question. Returns immediately with the queued
+    /// question id; the operator's answer arrives later as a
+    /// `HelperEvent::OperatorAnswered` in the manager inbox.
+    ///
+    /// - `options` is advisory: empty = free-text only; non-empty = the
+    ///   dashboard renders the choices alongside a free-text fallback
+    ///   ("Other…") so the operator is never trapped.
+    /// - `multi=true` lets the operator pick multiple options (rendered
+    ///   as checkboxes). The answer is returned as a single string with
+    ///   selections joined by ", ".
     AskOperator {
         question: String,
         #[serde(default)]
         options: Vec<String>,
+        #[serde(default)]
+        multi: bool,
     },
 }