revert: remove level meters and VU meter feature

Reverts:
- fix: move VU meter above volume controls to stop blocking mute button
- Merge feature/graph-ux-meters (region fix, toggle, segmented VU meters)
- Merge feature/level-meters (pw_stream peak metering, /api/peaks)

VU meters / level meters don't belong in a patchbay.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/components/GraphCanvas.svelte

@@ -1,7 +1,7 @@
 <script lang="ts">
   import { onMount, onDestroy } from 'svelte';
   import {
-    nodes, ports, links, connected, patchbay, peaks,
+    nodes, ports, links, connected, patchbay,
     portById,
     initGraph, destroyGraph,
     connectPorts, disconnectPorts,
@@ -139,22 +139,6 @@
     return $patchbay.aliases?.[nd.name] || nd.nick || nd.name;
   }
 
-  // Graph visibility toggle
-  let showGraph = $state(true);
-
-  // Level meter: returns how many of `total` segments should be lit
-  function meterSegs(nodeId: number, total: number): number {
-    const p = $peaks[nodeId] ?? 0;
-    if (p <= 0) return 0;
-    const db = Math.max(-60, 20 * Math.log10(p));
-    return Math.round(Math.max(0, (db + 60) / 60) * total);
-  }
-  // Segment color by position (0 = leftmost/quietest)
-  function segColor(i: number, total: number): string {
-    const pct = i / total;
-    return pct >= 0.90 ? '#c44' : pct >= 0.75 ? '#ca4' : '#4a9';
-  }
-
   // Build computed layout
   let graphNodes = $derived.by(() => {
     const n = $nodes;
@@ -210,7 +194,7 @@
       const headerH = 22;
       const portH = 16;
       const maxPorts = Math.max(allInPorts.length, allOutPorts.length, 1);
-      const height = headerH + maxPorts * portH + 36; // 20 for volume slider + 16 for VU meter
+      const height = headerH + maxPorts * portH + 20; // extra 20 for volume slider
       const width = 220;
 
       const portPositions = new Map<number, { x: number; y: number }>();
@@ -510,8 +494,6 @@
     </label>
 
     <span class="stats">{$nodes.length}N {$ports.length}P {$links.length}L {#if $patchbay.pinned_connections.length > 0}{$patchbay.pinned_connections.length}p{/if}</span>
-    <span class="sep"></span>
-    <button class="toggle" class:active={showGraph} onclick={() => showGraph = !showGraph} title="Show/hide graph canvas">Graph</button>
   </div>
 
   <!-- Virtual device dropdown -->
@@ -556,7 +538,6 @@
   {/if}
 
   <!-- svelte-ignore a11y_no_static_element_interactions -->
-  {#if showGraph}
   <svg
     bind:this={svgEl}
     viewBox="{viewBox.x} {viewBox.y} {viewBox.w} {viewBox.h}"
@@ -696,22 +677,9 @@
           {Math.round(Math.max(0, Math.min(1, nd.volume)) * 100)}%
         </text>
 
-        <!-- VU meter: 20 segmented LEDs (above the volume/mute controls) -->
-        {#each Array(20) as _, i}
-          <rect
-            x={nd.x + 8 + i * ((nd.width - 16) / 20)}
-            y={nd.y + nd.height - 35}
-            width={(nd.width - 16) / 20 - 1.5}
-            height="10"
-            rx="1"
-            fill={i < meterSegs(nd.id, 20) ? segColor(i, 20) : '#1e1e28'}
-          />
-        {/each}
-
       </g>
     {/each}
   </svg>
-  {/if}
 
   <!-- Context menu -->
   {#if contextMenu}
@@ -923,11 +891,11 @@
 </div>
 
 <style>
-  .wrap { width: 100%; height: 100vh; background: #14141e; display: flex; flex-direction: column; position: relative; overflow: hidden; user-select: none; -webkit-user-select: none; }
-  .canvas { flex: 1; min-height: 0; width: 100%; display: block; cursor: default; z-index: 1; user-select: none; -webkit-user-select: none; }
+  .wrap { width: 100%; height: 100vh; background: #14141e; position: relative; overflow: hidden; user-select: none; -webkit-user-select: none; }
+  .canvas { width: 100%; height: 100%; display: block; cursor: default; position: absolute; top: 0; left: 0; z-index: 1; user-select: none; -webkit-user-select: none; }
 
   .toolbar {
-    position: relative; flex-shrink: 0; z-index: 10;
+    position: absolute; top: 0; left: 0; right: 0; z-index: 10;
     display: flex; align-items: center; gap: 6px;
     padding: 4px 10px;
     background: rgba(16, 16, 24, 0.97);

frontend/src/lib/stores.ts

@@ -8,21 +8,6 @@ export const ports = writable<Port[]>([]);
 export const links = writable<Link[]>([]);
 export const connected = writable(false);
 
-// Level meter peaks: node_id → linear peak (0–1)
-export const peaks = writable<Record<number, number>>({});
-let peakInterval: ReturnType<typeof setInterval> | null = null;
-
-async function pollPeaks() {
-  try {
-    const res = await fetch('/api/peaks');
-    if (!res.ok) return;
-    const raw: Record<string, number> = await res.json();
-    const out: Record<number, number> = {};
-    for (const [k, v] of Object.entries(raw)) out[Number(k)] = v;
-    peaks.set(out);
-  } catch {}
-}
-
 // Patchbay state
 export const patchbay = writable<PatchbayState>({
   profiles: {},
@@ -117,8 +102,6 @@ export async function initGraph() {
   unsubscribe = subscribe((graph: GraphMessage) => {
     applyGraph(graph);
   });
-
-  peakInterval = setInterval(pollPeaks, 100);
 }
 
 export function destroyGraph() {
@@ -127,11 +110,6 @@ export function destroyGraph() {
     unsubscribe = null;
     connected.set(false);
   }
-  if (peakInterval) {
-    clearInterval(peakInterval);
-    peakInterval = null;
-  }
-  peaks.set({});
 }
 
 // Patchbay operations