fix(loudness): target sync, effective pre-analysis trim, and queue/settings copy (#333)

* fix(loudness): target sync, -14 pre-analysis ref, queue UI, and reseed

- Front: coalesce loudness refresh by target LUFS; replay-gain IPC dedupe keys
  include norm target and effective pre-attenuation so TGT changes apply.
- Rust: placeholder gain before integrated LUFS uses pivot at -14 LUFS; UI gain
  from effective trim; reseed loudness after delete when waveform cache would skip.
- Pre-analysis: store attenuation relative to -14 LUFS; engine and UI use an
  offset for other targets; migrate legacy absolute values on rehydrate.
- Queue/Settings: Loudness/TGT labels vs value buttons; styles; i18n for help.

* fix(i18n): simplify loudness pre-analysis helper copy

Remove reference-target wording from loudness pre-analysis helper text and keep
only the effective adjustment shown for the current LUFS target in all locales.

src/styles/layout.css

@@ -2007,6 +2007,17 @@ html[data-platform="windows"] .player-bar.floating {
   background: color-mix(in srgb, var(--accent) 14%, transparent);
 }
 
+.queue-current-tech-metric--lufs-reanalyze {
+  display: inline-flex;
+  align-items: baseline;
+  gap: 0;
+  padding: 2px 4px;
+  margin: -2px -4px;
+  max-width: 100%;
+  min-width: 0;
+  font-variant-numeric: tabular-nums;
+}
+
 .queue-divider {
   padding: var(--space-3) var(--space-4) 0;
   flex-shrink: 0;