feat: add Phase 4 Logging & Tracking — inline set logging, history views

Add workout logging so users can track sets, reps, weight, and a
"felt easy?" toggle inline from the workout day view via HTMX.
Sessions auto-create on first log. History page shows past sessions
with detailed per-exercise breakdowns.

New services: WorkoutSessionService, LogService
New routes: POST /log, /log/{id}/edit, /log/{id}/delete, GET /history, /history/{id}
New templates: log_form, log_entry, session_card, log_history, session_detail
Modified: exercise_card (inline logging), nav (History link), workouts route (session context)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/routes/workouts.py

@@ -4,6 +4,8 @@ Displays the warmup routine and main exercises for each workout day,
 with the active profile's programming targets.
 """
 
+from datetime import date
+
 import structlog
 from fastapi import APIRouter, Depends, Request
 from fastapi.responses import HTMLResponse
@@ -13,6 +15,8 @@ from app.database import get_db_session
 from app.models.user import User
 from app.models.user_exercise_program import UserExerciseProgram
 from app.services.exercise_service import ExerciseService
+from app.services.log_service import LogService
+from app.services.workout_session_service import WorkoutSessionService
 from app.utils.auth import get_current_admin_user, get_active_profile_id
 
 logger = structlog.get_logger(__name__)
@@ -77,6 +81,7 @@ async def workout_day_detail(
     active_profile_id = get_active_profile_id(request)
     programs = {}
     active_profile = None
+    existing_logs = {}
     if active_profile_id:
         active_profile = session.get(User, active_profile_id)
         if active_profile:
@@ -86,6 +91,27 @@ async def workout_day_detail(
             for prog in session.exec(statement).all():
                 programs[prog.exercise_id] = prog
 
+    # Look up the workout day ID for logging forms
+    days = exercise_service.list_workout_days()
+    workout_day_id = 0
+    for d in days:
+        if d.name == day_display:
+            workout_day_id = d.id
+            break
+
+    # Load existing logs for today's session (if any)
+    if active_profile_id and workout_day_id:
+        ws_service = WorkoutSessionService(session)
+        ws = ws_service.get_or_create_session(
+            user_id=active_profile_id,
+            workout_day_id=workout_day_id,
+            session_date=date.today(),
+        )
+        log_service = LogService(session)
+        all_logs = log_service.list_logs_for_session(ws.id)
+        for log in all_logs:
+            existing_logs.setdefault(log.exercise_id, []).append(log)
+
     templates = request.app.state.templates
     return templates.TemplateResponse("pages/workout_day.html", {
         "request": request,
@@ -94,5 +120,7 @@ async def workout_day_detail(
         "exercises": exercises,
         "programs": programs,
         "active_profile": active_profile,
+        "existing_logs": existing_logs,
+        "workout_day_id": workout_day_id,
         "admin": admin,
     })