fix(local-llm): show accurate macOS memory (app vs cached vs free)

Replace Node.js os.freemem() with vm_stat parsing for macOS. The old
approach reported ~47.7 GB / 48 GB 'used' because os.freemem() only
counts truly free pages, ignoring ~20 GB of inactive/reclaimable cache.

New memory breakdown:
- App Memory: active + wired + compressor (actual process usage)
- Cached: inactive + purgeable + speculative (reclaimable on demand)
- Available: free + cached (what apps can actually use)
- Pressure: normal/warning/critical based on app memory ratio

Dashboard UI updated to show app memory, cached (reclaimable) label,
and pressure-based color coding on progress bars.

__LOCAL_LLMs/dashboard/src/app/api/system/route.ts

@@ -89,23 +89,66 @@ async function getStaticInfo() {
   return staticCache;
 }
 
+// macOS vm_stat gives accurate memory breakdown (os.freemem() excludes reclaimable cache)
+async function getAccurateMemory(): Promise<{
+  total: number;
+  appMemory: number;
+  cached: number;
+  free: number;
+  pressure: string;
+}> {
+  const totalMem = os.totalmem();
+  try {
+    const { stdout } = await execAsync('vm_stat', { timeout: 2000 });
+    const pageSize = 16384; // macOS Apple Silicon default
+    const parse = (label: string): number => {
+      const match = stdout.match(new RegExp(`${label}:\\s+(\\d+)`));
+      return match ? parseInt(match[1]) * pageSize : 0;
+    };
+    const active = parse('Pages active');
+    const wired = parse('Pages wired down');
+    const inactive = parse('Pages inactive');
+    const purgeable = parse('Pages purgeable');
+    const speculative = parse('Pages speculative');
+    const free = parse('Pages free');
+    const compressor = parse('Pages occupied by compressor');
+
+    const appMemory = active + wired + compressor;
+    const cached = inactive + purgeable + speculative;
+    const trueFree = free + cached; // macOS reclaims cached on demand
+
+    const ratio = appMemory / totalMem;
+    const pressure = ratio > 0.85 ? 'critical' : ratio > 0.7 ? 'warning' : 'normal';
+
+    return { total: totalMem, appMemory, cached, free: trueFree, pressure };
+  } catch {
+    // Fallback to Node.js (inaccurate on macOS but works everywhere)
+    const freeMem = os.freemem();
+    return {
+      total: totalMem,
+      appMemory: totalMem - freeMem,
+      cached: 0,
+      free: freeMem,
+      pressure: 'unknown',
+    };
+  }
+}
+
 export async function GET() {
-  const [staticInfo, disk, ollamaDisk] = await Promise.all([
+  const [staticInfo, disk, ollamaDisk, memory] = await Promise.all([
     getStaticInfo(),
     getDiskSpace(),
     getOllamaModelsDiskUsage(),
+    getAccurateMemory(),
   ]);
 
-  const totalMem = os.totalmem();
-  const freeMem = os.freemem();
-  const usedMem = totalMem - freeMem;
   const cpuCount = os.cpus().length;
   const uptime = os.uptime();
 
   return NextResponse.json({
     chip: staticInfo.chip,
     gpu: staticInfo.gpu,
-    memory: { total: totalMem, used: usedMem, free: freeMem },
+    memory,
     disk,
     ollamaDiskUsage: ollamaDisk,
     cpuCores: cpuCount,

__LOCAL_LLMs/dashboard/src/app/page.tsx

@@ -75,7 +75,7 @@ interface WhisperData {
 interface SystemData {
   chip: string;
   gpu: string;
-  memory: { total: number; used: number; free: number };
+  memory: { total: number; appMemory: number; cached: number; free: number; pressure: string };
   disk: { total: number; used: number; free: number };
   ollamaDiskUsage: number;
   cpuCores: number;
@@ -428,18 +428,21 @@ export default function Dashboard() {
               MEMORY
             </span>
           </div>
-          <span className="text-lg font-bold">{formatBytes(system?.memory.used || 0)}</span>
+          <span className="text-lg font-bold">{formatBytes(system?.memory.appMemory || 0)}</span>
           <span className="text-sm ml-1" style={{ color: 'var(--text-tertiary)' }}>
             / {formatBytes(system?.memory.total || 0)}
           </span>
+          <p className="text-[10px] mt-0.5" style={{ color: 'var(--text-tertiary)' }}>
+            {formatBytes(system?.memory.cached || 0)} cached (reclaimable)
+          </p>
           <div className="mt-2">
             <ProgressBar
-              value={system?.memory.used || 0}
+              value={system?.memory.appMemory || 0}
               max={system?.memory.total || 1}
               color={
-                (system?.memory.used || 0) / (system?.memory.total || 1) > 0.85
+                system?.memory.pressure === 'critical'
                   ? 'var(--danger)'
-                  : (system?.memory.used || 0) / (system?.memory.total || 1) > 0.7
+                  : system?.memory.pressure === 'warning'
                     ? 'var(--warning)'
                     : 'var(--accent-primary)'
               }
@@ -750,14 +753,27 @@ export default function Dashboard() {
                     </span>
                   </div>
                   <span className="text-xs font-mono" style={{ color: 'var(--text-tertiary)' }}>
-                    {formatBytes(system?.memory.free || 0)} free
+                    {formatBytes(system?.memory.free || 0)} avail
                   </span>
                 </div>
                 <ProgressBar
-                  value={system?.memory.used || 0}
+                  value={system?.memory.appMemory || 0}
                   max={system?.memory.total || 1}
-                  color="var(--warning)"
+                  color={
+                    system?.memory.pressure === 'critical'
+                      ? 'var(--danger)'
+                      : system?.memory.pressure === 'warning'
+                        ? 'var(--warning)'
+                        : 'var(--accent-secondary)'
+                  }
                 />
+                <div
+                  className="flex justify-between mt-1 text-[10px]"
+                  style={{ color: 'var(--text-tertiary)' }}
+                >
+                  <span>App: {formatBytes(system?.memory.appMemory || 0)}</span>
+                  <span>Cache: {formatBytes(system?.memory.cached || 0)}</span>
+                </div>
               </div>
               <div>
                 <div className="flex items-center justify-between mb-1">