feat(queue): split tech bar into two lines when ReplayGain is present

The tech info strip in the queue header was a single ellipsised line, so
ReplayGain values (Track / Album / Peak) got cut off on tracks with a
full codec + bitrate + samplerate prefix. Now the strip wraps into two
lines whenever RG values exist:

- Line 1: codec · bitrate · bit depth/sample rate (unchanged)
- Line 2: 'ReplayGain · T … dB · A … dB · Peak …' — slightly smaller
  and dimmed for hierarchy, ellipsises independently if it still
  overflows.

Tracks without RG metadata stay one line as before. New i18n key
`queue.replayGain` ('ReplayGain') added to all 8 locales.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/styles/layout.css

@@ -1720,6 +1720,27 @@
   text-overflow: ellipsis;
 }
 
+/* Two-line layout: base info on top, ReplayGain underneath. The stack
+   wraps both spans so the source icon stays vertically centered next to
+   the whole text block. */
+.queue-current-tech-stack {
+  min-width: 0;
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  gap: 1px;
+}
+
+.queue-current-tech-rg {
+  min-width: 0;
+  max-width: 100%;
+  font-size: 8px;
+  opacity: 0.72;
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+
 .queue-divider {
   padding: var(--space-3) var(--space-4) 0;
   flex-shrink: 0;