feat(playback): loudness bind rules, analysis seeding, and normalization UI

Resolve integrated loudness from SQLite only at decode bind; keep pre-trim
until a row exists, then allow provisional gain from live updates. Pass
DB-stable hints from the web app into play and gapless preload.

Default pre-measurement attenuation -4.5 dB with an icon reset in Settings;
drop redundant normalization copy and shorten pre-trim descriptions.

analysis_cache seed_from_bytes returns an outcome and skips redundant
waveform work on cache hits; wire callers and related frontend/backend glue.

src/locales/de.ts

@@ -847,6 +847,12 @@ export const deTranslation = {
     replayGainAlbum: 'Album',
     replayGainPreGain: 'Pre-Gain (getaggte Dateien)',
     replayGainFallback: 'Fallback (ohne Tags / Radio)',
+    normalization: 'Normalisierung',
+    loudnessTargetLufs: 'Ziel-LUFS',
+    loudnessPreAnalysisAttenuation: 'Dämpfung vor Messung (dB)',
+    loudnessPreAnalysisAttenuationDesc:
+      'Zusätzliche Dämpfung, bis die Loudness des Titels gespeichert ist. Beim Streamen folgen nur grobe Schätzungen, keine volle Messung. 0 dB = aus; negativer = leiser.',
+    loudnessPreAnalysisAttenuationReset: 'Standard',
     crossfade: 'Crossfade',
     crossfadeDesc: 'Überblendung zwischen Tracks',
     crossfadeSecs: '{{n}} s',