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-tauri/src/lib.rs

@@ -1724,27 +1724,33 @@ fn analysis_delete_all_waveforms(
 fn analysis_enqueue_seed_from_url(
     track_id: String,
     url: String,
+    force: Option<bool>,
     app: tauri::AppHandle,
 ) -> Result<(), String> {
     if track_id.trim().is_empty() || url.trim().is_empty() {
         return Ok(());
     }
-    if let Some(engine) = app.try_state::<crate::audio::AudioEngine>() {
-        if crate::audio::ranged_loudness_backfill_should_defer(&engine, &track_id) {
-            crate::app_deprintln!(
-                "[analysis] backfill skip track_id={} reason=ranged_playback_will_seed",
-                track_id
-            );
-            return Ok(());
+    let force = force.unwrap_or(false);
+    if !force {
+        if let Some(engine) = app.try_state::<crate::audio::AudioEngine>() {
+            if crate::audio::ranged_loudness_backfill_should_defer(&engine, &track_id) {
+                crate::app_deprintln!(
+                    "[analysis] backfill skip track_id={} reason=ranged_playback_will_seed",
+                    track_id
+                );
+                return Ok(());
+            }
         }
     }
-    if let Some(cache) = app.try_state::<analysis_cache::AnalysisCache>() {
-        if cache.get_latest_loudness_for_track(&track_id)?.is_some() {
-            crate::app_deprintln!(
-                "[analysis] backfill skip (already cached): {}",
-                track_id
-            );
-            return Ok(());
+    if !force {
+        if let Some(cache) = app.try_state::<analysis_cache::AnalysisCache>() {
+            if cache.get_latest_loudness_for_track(&track_id)?.is_some() {
+                crate::app_deprintln!(
+                    "[analysis] backfill skip (already cached): {}",
+                    track_id
+                );
+                return Ok(());
+            }
         }
     }
     let tid_log = track_id.clone();