feat: reveal all hidden shapes with Shift+H, release SAM3 VRAM on idle and on demand (REQ-191, REQ-192)

frontend/src/components/Sidebar.jsx

@@ -17,6 +17,7 @@ import {
 
 export default function Sidebar({ route, currentProject, theme, onToggleTheme }) {
   const [health, setHealth] = useState(null)
+  const [notice, setNotice] = useState('')
 
   useEffect(() => {
     let timer
@@ -28,6 +29,18 @@ export default function Sidebar({ route, currentProject, theme, onToggleTheme })
     return () => clearInterval(timer)
   }, [])
 
+  // REQ-192: free the SAM3 model's VRAM on demand; the 3 s health poll is what
+  // confirms it, this only flips the badge straight away when it worked.
+  const releaseSam3 = async () => {
+    try {
+      await api.releaseSam3()
+      setHealth((current) => (current ? { ...current, model_loaded: false } : current))
+    } catch (exc) {
+      setNotice(exc.message)
+      setTimeout(() => setNotice(''), 4000)
+    }
+  }
+
 
   const pId = currentProject?.id || route.projectId || 1
 
@@ -138,9 +151,28 @@ export default function Sidebar({ route, currentProject, theme, onToggleTheme })
             <span className="health-badge">
               VRAM: {health.vram_free_gb ? `${health.vram_free_gb.toFixed(1)}GB` : 'N/A'}
             </span>
-            <span className={`health-badge ${health.sam3_ready ? 'ready' : ''}`}>
-              SAM3: {health.sam3_ready ? 'Ready' : 'Off'}
-            </span>
+            {notice && <span className="health-badge">{notice}</span>}
+            {!health.sam3_ready ? (
+              <span className="health-badge" title="Not enough free VRAM for SAM3 — free the card first">
+                SAM3: Off
+              </span>
+            ) : health.model_loaded ? (
+              <button
+                type="button"
+                className="health-badge ready"
+                title="SAM3 is in VRAM (~3.9 GB) — click to free it now"
+                onClick={releaseSam3}
+              >
+                SAM3: Loaded
+              </button>
+            ) : (
+              <span
+                className="health-badge ready"
+                title="SAM3 not in VRAM — it loads on the next use (~12 s)"
+              >
+                SAM3: Idle
+              </span>
+            )}
           </div>
         )}