Add per-exercise personal record tracking

Session tracking only ever stored a done boolean - no record of what
weight or reps were actually performed, so there was no way to derive
real progress data even though the dashboard implied "progress
tracking" was a thing. Workout templates only hold a static planned
value, not a history of performance.

Adds actual_weight/actual_reps to workout_session_items, captured
inline when checking off a set in a session (defaults to the workout's
planned weight/reps, editable before confirming). The exercise detail
page now shows the user's personal best (heaviest completed set, tie
broken by reps) computed from their completed session history across
all workouts containing that exercise.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

lang/en/app.php

@@ -192,6 +192,8 @@ return [
                 'rename_reset' => 'Reset',
                 'renamed_success' => 'Your custom name has been saved.',
                 'rename_cleared' => 'Custom name cleared.',
+        'personal_best' => 'Your Personal Best',
+        'no_personal_best' => 'No completed sets logged yet. Track weight and reps when you check off a set in a session.',
     ],
 
     'sessions' => [
@@ -211,7 +213,9 @@ return [
         'rest_timer' => 'Rest timer',
         'start_rest' => 'Start',
         'pause_rest' => 'Pause',
-        'reset_rest' => 'Reset'
+        'reset_rest' => 'Reset',
+        'weight_lifted' => 'Weight',
+        'reps_done' => 'Reps',
     ],
 
     'dashboard' => [

lang/ro/app.php

@@ -192,6 +192,8 @@ return [
                         'rename_reset' => 'Resetează',
                         'renamed_success' => 'Numele personalizat a fost salvat.',
                         'rename_cleared' => 'Numele personalizat a fost eliminat.',
+        'personal_best' => 'Recordul tău personal',
+        'no_personal_best' => 'Niciun set finalizat înregistrat încă. Înregistrează greutatea și repetările când bifezi un set într-o sesiune.',
     ],
 
     'sessions' => [
@@ -211,7 +213,9 @@ return [
         'rest_timer' => 'Cronometru pauză',
         'start_rest' => 'Start',
         'pause_rest' => 'Pauză',
-        'reset_rest' => 'Reset'
+        'reset_rest' => 'Reset',
+        'weight_lifted' => 'Greutate',
+        'reps_done' => 'Repetări',
     ],
 
     'dashboard' => [