feat(fitness): auto-advance exercises with view transitions + audio cues

Last set of an exercise auto-advances to the next unfinished exercise.
View Transitions API animates the swap: vertical slide on the exercise
name and set-counter row, horizontal slide on the set table at >=900px.
Three Web Audio cues — per-set tick, exercise-complete two-note rise,
and workout-complete fanfare on the completion overview.

src/lib/components/fitness/WorkoutFocusCard.svelte

@@ -120,6 +120,7 @@
 		line-height: 1.15;
 		color: var(--color-text-primary);
 		min-width: 0;
+		view-transition-name: workout-focus-name;
 	}
 	.focus-details {
 		flex-shrink: 0;
@@ -146,6 +147,7 @@
 		justify-content: space-between;
 		gap: 1rem;
 		flex-wrap: wrap;
+		view-transition-name: workout-focus-progress;
 	}
 	.focus-set-label {
 		font-size: 0.78rem;

src/lib/js/fitnessSounds.ts

@@ -0,0 +1,99 @@
+/**
+ * Lightweight Web Audio cues for the active workout.
+ * One shared AudioContext is reused across calls so we don't leak contexts.
+ */
+
+let _ctx: AudioContext | null = null;
+
+function _getCtx(): AudioContext | null {
+	if (typeof window === 'undefined') return null;
+	try {
+		if (!_ctx) {
+			const Ctor = window.AudioContext ?? (window as any).webkitAudioContext;
+			if (!Ctor) return null;
+			_ctx = new Ctor();
+		}
+		if (_ctx.state === 'suspended') _ctx.resume().catch(() => {});
+		return _ctx;
+	} catch {
+		return null;
+	}
+}
+
+type Note = {
+	freq: number;
+	start: number;
+	dur: number;
+	gain?: number;
+	type?: OscillatorType;
+};
+
+function _playNotes(notes: Note[]) {
+	const ctx = _getCtx();
+	if (!ctx) return;
+	const now = ctx.currentTime;
+	for (const n of notes) {
+		try {
+			const osc = ctx.createOscillator();
+			const gain = ctx.createGain();
+			osc.type = n.type ?? 'sine';
+			osc.frequency.value = n.freq;
+			const peak = n.gain ?? 0.18;
+			gain.gain.setValueAtTime(0.0001, now + n.start);
+			gain.gain.exponentialRampToValueAtTime(peak, now + n.start + 0.012);
+			gain.gain.exponentialRampToValueAtTime(0.0001, now + n.start + n.dur);
+			osc.connect(gain).connect(ctx.destination);
+			osc.start(now + n.start);
+			osc.stop(now + n.start + n.dur + 0.02);
+		} catch {}
+	}
+}
+
+/**
+ * Short, bright "check" cue played when a single set is marked complete.
+ * Two stacked sine tones a fifth apart for a quick, satisfying tick.
+ */
+export function playSetCompleteSound() {
+	_playNotes([
+		{ freq: 880, start: 0, dur: 0.09, gain: 0.18 }, // A5
+		{ freq: 1320, start: 0.05, dur: 0.11, gain: 0.13 } // E6
+	]);
+}
+
+/**
+ * Two-note rise played when the final set of an exercise is checked and we
+ * auto-advance. Sequential (vs. the per-set tick's stacked fifth) so it reads
+ * as a small step up — not a fanfare.
+ */
+export function playExerciseCompleteSound() {
+	_playNotes([
+		{ freq: 880, start: 0.0, dur: 0.12, gain: 0.18 }, // A5
+		{ freq: 1318.51, start: 0.1, dur: 0.18, gain: 0.16 } // E6
+	]);
+}
+
+/**
+ * Triumphant fanfare for whole-workout completion: a rising C-major arpeggio
+ * resolving onto a sustained tonic triad with an upper-octave highlight.
+ */
+export function playWorkoutCompleteSound() {
+	const notes: Note[] = [
+		// Quick rising arpeggio
+		{ freq: 523.25, start: 0.0, dur: 0.14, gain: 0.18 }, // C5
+		{ freq: 659.25, start: 0.1, dur: 0.14, gain: 0.18 }, // E5
+		{ freq: 783.99, start: 0.2, dur: 0.14, gain: 0.18 }, // G5
+		{ freq: 1046.5, start: 0.3, dur: 0.18, gain: 0.2 }, // C6
+		// A brief V chord (G major) before resolution for a fanfare feel
+		{ freq: 783.99, start: 0.48, dur: 0.22, gain: 0.15 }, // G5
+		{ freq: 987.77, start: 0.48, dur: 0.22, gain: 0.12 }, // B5
+		{ freq: 1174.66, start: 0.48, dur: 0.22, gain: 0.1 }, // D6
+		// Sustained tonic triad with octave doubling
+		{ freq: 523.25, start: 0.72, dur: 1.1, gain: 0.16 }, // C5
+		{ freq: 659.25, start: 0.72, dur: 1.1, gain: 0.13 }, // E5
+		{ freq: 783.99, start: 0.72, dur: 1.1, gain: 0.13 }, // G5
+		{ freq: 1046.5, start: 0.72, dur: 1.1, gain: 0.12 }, // C6
+		// Bright highlight on top
+		{ freq: 1568.0, start: 0.88, dur: 0.55, gain: 0.09 } // G6
+	];
+	_playNotes(notes);
+}