feat(01-02): integrate WeightInput and RepsInput into ExerciseCard set rows

- Import WeightInput and RepsInput in WorkoutPage.jsx
- Replace bare <input type="number"> elements with stepper components
- Update .set-inputs alignment to flex-start for taller steppers
- Update .set-row alignment to flex-start
- Remove now-redundant .weight-input and .reps-input CSS rules (main + mobile)

frontend/src/pages/WorkoutPage.jsx

@@ -1,5 +1,7 @@
 import { useState, useEffect } from 'react'
 import { Icon } from '../components/Icons'
+import WeightInput from '../components/WeightInput'
+import RepsInput from '../components/RepsInput'
 
 // Uppvärmningsövningar baserat på muskelgrupp
 const warmupExercises = {
@@ -324,22 +326,14 @@ function ExerciseCard({ exercise, logs, progression, expanded, onToggle, onLogSe
                 <div key={setNum} className={`set-row ${input.completed ? 'completed' : ''}`}>
                   <span className="set-number">Set {setNum}</span>
                   <div className="set-inputs">
-                    <input
-                      type="number"
-                      placeholder="kg"
+                    <WeightInput
                       value={input.weight}
-                      onChange={(e) => handleInputChange(setNum, 'weight', e.target.value)}
-                      className="weight-input"
-                      inputMode="decimal"
+                      onChange={(val) => handleInputChange(setNum, 'weight', val)}
                     />
                     <span className="input-separator">×</span>
-                    <input
-                      type="number"
-                      placeholder="reps"
+                    <RepsInput
                       value={input.reps}
-                      onChange={(e) => handleInputChange(setNum, 'reps', e.target.value)}
-                      className="reps-input"
-                      inputMode="numeric"
+                      onChange={(val) => handleInputChange(setNum, 'reps', val)}
                     />
                   </div>
                   <button