fix: property inspector - read sample rate from node.latency, not node.rate

- node.rate was a PipeWire internal flag (always 1), not sample rate
- Now reads from node.latency (format: '256/48000') for quantum + rate
- Fallback to clock.rate if latency not available
- Reuses rate field for ALSA period-size
- Shows 'Latency: 256 samples @ 48000 Hz' and 'Period Size: 256'

frontend/src/components/GraphCanvas.svelte

@@ -693,8 +693,8 @@
             {#if nd.sample_rate > 0}<tr><td class="pk">Sample Rate</td><td>{nd.sample_rate} Hz</td></tr>{/if}
             {#if nd.channels > 0}<tr><td class="pk">Channels</td><td>{nd.channels}</td></tr>{/if}
             {#if nd.format}<tr><td class="pk">Format</td><td>{nd.format}</td></tr>{/if}
-            {#if nd.quantum > 0}<tr><td class="pk">Quantum</td><td>{nd.quantum}</td></tr>{/if}
+            {#if nd.quantum > 0}<tr><td class="pk">Latency</td><td>{nd.quantum} samples @ {nd.sample_rate} Hz</td></tr>{/if}
-            {#if nd.rate > 0}<tr><td class="pk">Rate</td><td>{nd.rate}</td></tr>{/if}
+            {#if nd.rate > 0}<tr><td class="pk">Period Size</td><td>{nd.rate}</td></tr>{/if}
             {#if nd.device_name}<tr><td class="pk">Device</td><td>{nd.device_name}</td></tr>{/if}
             {#if nd.device_bus}<tr><td class="pk">Bus</td><td>{nd.device_bus}</td></tr>{/if}
             {#if nd.api}<tr><td class="pk">API</td><td>{nd.api}</td></tr>{/if}

src/graph_engine.cpp

@@ -125,8 +125,26 @@ static void on_node_info(void *data, const struct pw_node_info *info) {
             str = spa_dict_lookup(info->props, "priority.driver");
             if (str) nobj->node.priority = atoi(str);
 
-            str = spa_dict_lookup(info->props, "node.rate");
+            // Latency info
-            if (str) nobj->node.rate = (uint32_t)atoi(str);
+            str = spa_dict_lookup(info->props, "node.latency");
+            if (str) {
+                // Format: "256/48000" -> quantum=256 rate=48000
+                uint32_t q = 0, r = 0;
+                if (sscanf(str, "%u/%u", &q, &r) == 2) {
+                    nobj->node.quantum = q;
+                    nobj->node.sample_rate = r;
+                }
+            }
+
+            // Fallback: read clock rate from device props
+            if (nobj->node.sample_rate == 0) {
+                str = spa_dict_lookup(info->props, "clock.rate");
+                if (str) nobj->node.sample_rate = (uint32_t)atoi(str);
+            }
+
+            // ALSA latency
+            str = spa_dict_lookup(info->props, "api.alsa.period-size");
+            if (str) nobj->node.rate = (uint32_t)atoi(str); // reuse rate field for period-size
         }
     }