fix(ui,install): Models page couldn't scroll to installed models; report install result in original window

Models.jsx clipped the whole card with overflow:hidden while only the
"Available Models" section (never visible when the hardware-recommended
list alone filled the card) had its own scroll — the installed-models
list was unreachable with no scrollbar. The whole card now scrolls as
one region instead.

install-windows.ps1's original (non-elevated) window printed "Requesting
administrator privileges..." and exited immediately, so all real
progress and the "installed!" banner only ever appeared in the separate
elevated window — making the original window look like it silently
quit. It now waits (-Wait -PassThru) and reports success/failure itself.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

interface/web/src/Models.jsx

@@ -161,7 +161,8 @@ export function Models({ onPullStateChange }) {
         padding: "1rem",
         display: "flex",
         flexDirection: "column",
-        overflow: "hidden"
+        overflowY: "auto",
+        overflowX: "hidden"
       }}>
         {/* Pull Model Section */}
         <div style={{ marginBottom: "1.5rem", paddingBottom: "1rem", borderBottom: "1px solid #333" }}>
@@ -260,7 +261,7 @@ export function Models({ onPullStateChange }) {
         )}
 
         {/* Local Models List */}
-        <div style={{ flexGrow: 1, overflowY: "auto", paddingRight: "0.5rem" }}>
+        <div style={{ paddingRight: "0.5rem" }}>
           <h3 style={{ margin: "0 0 1rem 0", fontSize: "0.95rem", color: "#bbb" }}>
             Available Models ({models.length})
           </h3>