fix(gate): stop injecting the redundant Altro option on select gates

buildSelectRequest injected an `altroOption` ({id:"other", opens:freetext}) into the
select descriptor, but SelectWidget/MultiselectWidget never route option.opens — so it
rendered as an inert "Altro — specifica…" button next to the working reserved
"Other — specify" control (which now owns free-text since the reviewer-gate-ux fix).
Remove the injection, the now-unused altroOption()/ALTRO_LABEL, and the unused
allow_other flag from both builders (no frontend consumer). Free-text stays offered on
every gate via the reserved "Other" control. The ArtifactGateWidget opens/LinkageHost
linkage (reject-with-reason capability) is intentionally kept — it is a separate,
tested feature, not the injected duplicate.

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

harness/.pi/extensions/gate/builders.js

@@ -15,7 +15,6 @@
 const SCHEMA_VERSION = 1;
 const RESERVED = ["back", "exit", "other"];
 
-const ALTRO_LABEL = "Altro — specifica…";
 const VALID_ACTION_KINDS = new Set(["confirm", "approve_reject", "view_only"]);
 const VALID_INFO_LEVELS = new Set(["info", "warning", "error"]);
 
@@ -33,21 +32,12 @@ function requireArray(value, name, ctx) {
   return value;
 }
 
-// An "other" option that opens a freetext child widget. Always present on
-// blocking pick widgets so the reviewer is never trapped in the listed options.
-function altroOption() {
-  return {
-    id: "other",
-    label: ALTRO_LABEL,
-    opens: { widget: "freetext", title: "Specifica…" },
-  };
-}
-
-// Build a `select` ui_request (single-pick). Reserved hatches (Altro/Back/Exit)
-// are injected; Altro carries the freetext linkage (§4.2). `recommended` is the
-// id of the option to highlight as "(consigliato)".
+// Build a `select` ui_request (single-pick). The framework escape hatches
+// (Back/Exit/Other) come from `reserved` (rendered by ReservedControls, which owns
+// the free-text linkage on "Other"). `recommended` is the id of the option to
+// highlight as "(consigliato)".
 function buildSelectRequest({
-  id, phase, title, options, intro = null, allowOther = true, recommended = null,
+  id, phase, title, options, intro = null, recommended = null,
 }) {
   requireString(title, "title", "select");
   const opts = requireArray(options, "options", "select");
@@ -59,9 +49,8 @@ function buildSelectRequest({
     widget: "select",
     title,
     intro,
-    allow_other: allowOther,
     recommended,
-    options: allowOther ? [...opts, altroOption()] : [...opts],
+    options: [...opts],
     reserved: RESERVED,
   };
   return out;
@@ -71,7 +60,7 @@ function buildSelectRequest({
 // context (e.g. schema candidates); `selected` the pre-checked option ids;
 // `allowEmpty:false` with zero options is a broken widget and throws.
 function buildMultiselectRequest({
-  id, phase, title, options, content = null, selected = [], allowEmpty = false, allowOther = true,
+  id, phase, title, options, content = null, selected = [], allowEmpty = false,
 }) {
   requireString(title, "title", "multiselect");
   const opts = requireArray(options, "options", "multiselect");
@@ -88,7 +77,6 @@ function buildMultiselectRequest({
     widget: "multiselect",
     title,
     allow_empty: allowEmpty,
-    allow_other: allowOther,
     options: [...opts],
     selected: [...selected],
     content,