fitness: add complete fitness tracker frontend

- 5-tab layout (Profile, History, Workout, Exercises, Measure) with shared header nav
- Workout system: template CRUD, active workout on /fitness/workout/active with localStorage persistence, pause/resume timer, rest timer, RPE input
- Shared workout singleton (getWorkout) so active workout state is accessible across all fitness routes
- Floating workout FAB indicator on all /fitness routes when workout is active
- AddActionButton component for button-based FABs (measure + template creation)
- Profile page with workouts-per-week bar chart and weight line chart with SMA trend line + ±1σ confidence band
- Exercise detail with history, charts, and records tabs using static exercise data
- Session history with grouped-by-month list, session detail with stats/PRs
- Body measurements with latest values, body part display, add form
- Card styling matching rosary/prayer route patterns (accent-dark, nord5 light, box-shadow, hover lift)
- FitnessChart: fix SSR hang by moving Chart.register to client-side, remove redundant $effect
- Exercise API: use static in-repo data instead of empty MongoDB collection
- Workout finish: include exercise name for WorkoutSession model validation

src/lib/components/fitness/WorkoutFab.svelte

@@ -0,0 +1,88 @@
+<script>
+import "$lib/css/action_button.css"
+import { Dumbbell } from 'lucide-svelte';
+
+let { href, elapsed = '0:00', paused = false } = $props();
+</script>
+
+<style>
+.container{
+position: fixed;
+bottom:0;
+right:0;
+width: 1rem;
+height: 1rem;
+padding: 2rem;
+border-radius: var(--radius-pill);
+margin: 2rem;
+transition: var(--transition-normal);
+background-color: var(--red);
+display: grid;
+justify-content: center;
+align-content: center;
+z-index: 100;
+text-decoration: none;
+}
+@media screen and (max-width: 500px) {
+	.container{
+		margin: 1rem;
+	}
+}
+
+.timer {
+	font-variant-numeric: tabular-nums;
+	font-weight: 700;
+	font-size: 0.85rem;
+	color: white;
+	line-height: 1;
+	text-align: center;
+}
+.timer.paused {
+	color: var(--nord13);
+}
+
+:root{
+    --angle: 15deg;
+}
+.container:hover,
+.container:focus-within
+{
+	background-color: var(--nord0);
+box-shadow: 0em 0em 0.5em 0.5em rgba(0,0,0,0.2);
+	animation: shake 0.5s;
+	animation-fill-mode: forwards;
+}
+
+@keyframes shake{
+    0%{
+      transform: rotate(0)
+		scale(1,1);
+    }
+    25%{
+    	box-shadow: 0em 0em 1em 0.2em rgba(0, 0, 0, 0.6);
+      	transform: rotate(var(--angle))
+      		scale(1.2,1.2)
+      ;
+    }
+    50%{
+
+    	box-shadow: 0em 0em 1em 0.2em rgba(0, 0, 0, 0.6);
+      	transform: rotate(calc(-1* var(--angle)))
+      		scale(1.2,1.2);
+    }
+    74%{
+
+    	box-shadow: 0em 0em 1em 0.2em rgba(0, 0, 0, 0.6);
+  	transform: rotate(var(--angle))
+  		scale(1.2, 1.2);
+	}
+	100%{
+      transform: rotate(0)
+      scale(1.2,1.2);
+    }
+  }
+</style>
+<a class="container action_button" {href} aria-label="Return to active workout">
+	<span class="timer" class:paused>{elapsed}</span>
+	<Dumbbell size={26} color="white" />
+</a>