Fix wave: scroll-lock without layout shift; every models write mirrors the stored record

Fix 1 (owner: "lock must not shift"): the settings dialog's scroll-lock no
longer toggles the content column to overflow-hidden (which hid the
scrollbar and shifted everything right). The column KEEPS overflow-y-auto —
scrollbar and widths stay exactly as they are — and while any MenuShell is
open, non-passive wheel + touchmove listeners on the column preventDefault
so it cannot scroll (owner-ruled mechanism: the scrollbar may stay,
scrolling must not happen, nothing may move). Native listeners via ref —
React attaches synthetic wheel/touch passively at the root.

Fix 2 (owner repro: xhigh pin survives a GLM swap on screen until reload):
every models-writing surface now mirrors SERVER TRUTH, never the request
body. The PUT already returns the full stored record with clamps applied —
settings-dialog write() and the composer's save() now setRecord/setModels
from the response, so a swap that rides an unsupported level shows the
clamped value in the same interaction: the row trigger, the open menu's
level list + checkmark, and the composer pill all read the stored record.

Live-verified the owner's exact repro: deepseek pinned extra high → GLM
swap via the slot menu → trigger/menu/pill showed the stored clamped level
immediately; and the lock cycle: scroll 300 → blocked while open → 300
after release, zero positional shift at engage.

components/model-picker.tsx

@@ -1,7 +1,7 @@
 "use client";
 
 import { useCallback, useEffect, useRef, useState } from "react";
-import type { ModelCatalogEntry, ModelCatalogResponse, ModelsSettings } from "@/src/core";
+import type { ModelCatalogEntry, ModelCatalogResponse, ModelsSettings, UserSettings } from "@/src/core";
 import type { ThinkingLevel } from "@earendil-works/pi-agent-core";
 import { prettyModel } from "@/components/usage-format";
 import { ModelMenuList, ThinkingMenuList } from "@/components/settings/model-menu";
@@ -172,7 +172,13 @@ export function ModelControl() {
 					setError(body.error ?? `settings rejected (${res.status})`);
 					return;
 				}
-				setModels(next);
+				// Server truth, never the request body (fix wave): a pick
+				// that rides an unsupported level lands CLAMPED in the record
+				// — the pill must show the stored value in this interaction.
+				const stored = (
+					(await res.json().catch(() => null)) as { settings?: UserSettings } | null
+				)?.settings?.models;
+				setModels(stored ?? next);
 				setOpen(null);
 				notifySettingsSaved("models");
 			} catch {