Feature: nutrition module (keto macros + intermittent fasting + electrolytes)

Backend:
- models/nutrition.py: NutritionGoal, Fast, ElectrolyteLog tables
- schemas/nutrition.py: Pydantic schemas for new endpoints
- routers/nutrition.py: /api/nutrition/{today,goals,fasts,electrolytes}
- main.py: register router + migration for new tables + seed keto point rules

Frontend:
- pages/Nutrition.jsx: macro bars, fast timer, eating window, electrolyte quick-add
- App.jsx: /nutrition route + Keto nav tab
- api.js: nutrition endpoints

Points schema for fasts (tier-based partial credit):
16:8=25, 18:6=40, 20:4=60, 24h=200, 36h=350, 48h=500, 72h=1000

Defaults tuned for Scot: 135kg M 44yo strict keto, 12:00-20:00 window,
Asia/Bangkok timezone, 2400/2600 cal rest/training, 20g net carb cap.

backend/app/models/__init__.py

@@ -9,6 +9,7 @@ from app.models.oauth import OAuthToken
 from app.models.resource import Resource
 from app.models.catalog import ProgramCatalog, CatalogWorkout, CrawlQueue, WorkoutLog
 from app.models.support import SupportThread, SupportMessage
+from app.models.nutrition import NutritionGoal, Fast, ElectrolyteLog
 
 __all__ = [
     "User", "UserProfile", "Program", "ActivityLog", "FoodLog",
@@ -16,4 +17,5 @@ __all__ = [
     "OAuthToken", "Resource",
     "ProgramCatalog", "CatalogWorkout", "CrawlQueue", "WorkoutLog",
     "SupportThread", "SupportMessage",
+    "NutritionGoal", "Fast", "ElectrolyteLog",
 ]

backend/app/models/nutrition.py

@@ -0,0 +1,90 @@
+from __future__ import annotations
+
+import uuid
+from datetime import datetime, timezone
+from decimal import Decimal
+from sqlalchemy import String, Integer, Numeric, DateTime, Boolean, Text, ForeignKey, Index
+from sqlalchemy.orm import Mapped, mapped_column
+from sqlalchemy.dialects.postgresql import UUID
+from app.database import Base
+
+
+class NutritionGoal(Base):
+    """Per-user macro + eating-window targets. One active per user."""
+    __tablename__ = "nutrition_goals"
+
+    id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
+    user_id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), ForeignKey("users.id"), nullable=False, unique=True)
+
+    # Macro targets (grams / kcal)
+    calorie_target: Mapped[int] = mapped_column(Integer, default=2400)
+    protein_g_target: Mapped[int] = mapped_column(Integer, default=180)
+    fat_g_target: Mapped[int] = mapped_column(Integer, default=175)
+    net_carbs_g_cap: Mapped[int] = mapped_column(Integer, default=20)  # strict keto
+
+    # Training-day override (optional)
+    training_calorie_target: Mapped[int | None] = mapped_column(Integer)
+    training_protein_g_target: Mapped[int | None] = mapped_column(Integer)
+    training_fat_g_target: Mapped[int | None] = mapped_column(Integer)
+
+    # Eating window (24h local time, hours only)
+    eating_window_start_hour: Mapped[int] = mapped_column(Integer, default=12)  # 12:00
+    eating_window_end_hour: Mapped[int] = mapped_column(Integer, default=20)    # 20:00
+    default_fast_hours: Mapped[int] = mapped_column(Integer, default=16)        # 16:8
+
+    diet_style: Mapped[str] = mapped_column(String(30), default="strict_keto")
+    timezone_str: Mapped[str] = mapped_column(String(50), default="Asia/Bangkok")
+
+    is_active: Mapped[bool] = mapped_column(Boolean, default=True)
+    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=lambda: datetime.now(timezone.utc))
+    updated_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=lambda: datetime.now(timezone.utc))
+
+
+class Fast(Base):
+    """A single fasting bout — start/end + type + compliance flag."""
+    __tablename__ = "fasts"
+
+    id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
+    user_id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), ForeignKey("users.id"), nullable=False)
+
+    started_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False)
+    ended_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
+
+    # Target length (hours) — 16, 18, 20, 24, 36, 48, 72
+    target_hours: Mapped[int] = mapped_column(Integer, nullable=False)
+    fast_type: Mapped[str] = mapped_column(String(20), default="daily")  # daily, weekly_24, long_48, long_72, extended
+
+    # Completion state
+    completed: Mapped[bool] = mapped_column(Boolean, default=False)  # hit target
+    broken_early: Mapped[bool] = mapped_column(Boolean, default=False)  # ended before target
+
+    # Points granted (for idempotency — don't double-credit)
+    points_awarded: Mapped[int] = mapped_column(Integer, default=0)
+    activity_log_id: Mapped[uuid.UUID | None] = mapped_column(UUID(as_uuid=True), ForeignKey("activity_log.id"))
+
+    notes: Mapped[str | None] = mapped_column(Text)
+
+    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=lambda: datetime.now(timezone.utc))
+
+    __table_args__ = (
+        Index("idx_fasts_user_started", "user_id", "started_at"),
+    )
+
+
+class ElectrolyteLog(Base):
+    """Daily electrolyte dosing checklist — lightweight tracker."""
+    __tablename__ = "electrolyte_log"
+
+    id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
+    user_id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), ForeignKey("users.id"), nullable=False)
+    log_date: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False)
+
+    sodium_mg: Mapped[int] = mapped_column(Integer, default=0)
+    potassium_mg: Mapped[int] = mapped_column(Integer, default=0)
+    magnesium_mg: Mapped[int] = mapped_column(Integer, default=0)
+
+    notes: Mapped[str | None] = mapped_column(Text)
+
+    __table_args__ = (
+        Index("idx_electrolyte_user_date", "user_id", "log_date"),
+    )