Pin versions, add resource limits, and harden config

- Pin all Docker image tags (mysql 8.0.40, python 3.12.13-slim, node 20.20.1-alpine, nginx 1.29.6-alpine)
- Pin all frontend npm dependencies to exact versions (remove ^ ranges)
- Add mem_limit and cpus resource limits to all three containers
- Add non-root appuser to backend Dockerfile
- Migrate JWT from python-jose to PyJWT
- Remove default admin_password in config.py — must be explicitly set in .env
- Add DOCS_ENABLED flag to config and .env.example (default false)
- Add indexes on session_date, is_active, event_type in session models
- Add limit/offset pagination to all log endpoints

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

backend/Dockerfile

@@ -1,4 +1,4 @@
-FROM python:3.12-slim
+FROM python:3.12.13-slim
 
 WORKDIR /app
 
@@ -11,6 +11,11 @@ RUN pip install --no-cache-dir -r requirements.txt
 
 COPY . .
 
+RUN adduser --disabled-password --gecos '' --uid 1000 appuser \
+    && chown -R appuser /app
+
+USER appuser
+
 EXPOSE 8000
 
 CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "8000"]

backend/app/auth/jwt.py

@@ -1,7 +1,8 @@
 from datetime import datetime, timedelta, timezone
 from typing import Any
 
-from jose import JWTError, jwt
+import jwt
+from jwt import PyJWTError
 from passlib.context import CryptContext
 
 from app.config import get_settings
@@ -43,5 +44,5 @@ def create_refresh_token(data: dict[str, Any]) -> str:
 def decode_token(token: str) -> dict[str, Any]:
     try:
         return jwt.decode(token, settings.secret_key, algorithms=[settings.algorithm])
-    except JWTError:
+    except PyJWTError:
         raise ValueError("Invalid or expired token")

backend/app/config.py

@@ -10,7 +10,8 @@ class Settings(BaseSettings):
     refresh_token_expire_days: int = 30
     cors_origins: str = "http://localhost:8054"
     admin_username: str = "admin"
-    admin_password: str = "change_me_admin_password"
+    admin_password: str  # no default — must be explicitly set in .env
+    docs_enabled: bool = False
 
     @property
     def cors_origins_list(self) -> list[str]:

backend/app/models/session.py

@@ -21,8 +21,8 @@ class DailySession(TimestampMixin, Base):
     template_id: Mapped[int | None] = mapped_column(
         ForeignKey("schedule_templates.id", ondelete="SET NULL"), nullable=True
     )
-    session_date: Mapped[date] = mapped_column(Date, nullable=False)
-    is_active: Mapped[bool] = mapped_column(default=True)
+    session_date: Mapped[date] = mapped_column(Date, nullable=False, index=True)
+    is_active: Mapped[bool] = mapped_column(default=True, index=True)
     current_block_id: Mapped[int | None] = mapped_column(
         ForeignKey("schedule_blocks.id", ondelete="SET NULL"), nullable=True
     )
@@ -48,7 +48,7 @@ class TimerEvent(Base):
     block_id: Mapped[int | None] = mapped_column(
         ForeignKey("schedule_blocks.id", ondelete="SET NULL"), nullable=True
     )
-    event_type: Mapped[str] = mapped_column(String(20), nullable=False)
+    event_type: Mapped[str] = mapped_column(String(20), nullable=False, index=True)
     occurred_at: Mapped[datetime] = mapped_column(DateTime, default=func.now(), server_default=func.now())
 
     session: Mapped["DailySession"] = relationship("DailySession", back_populates="timer_events")

backend/app/routers/logs.py

@@ -24,6 +24,8 @@ async def get_timeline(
     log_date: date | None = None,
     date_from: date | None = None,
     date_to: date | None = None,
+    limit: int = 500,
+    offset: int = 0,
     current_user: User = Depends(get_current_user),
     db: AsyncSession = Depends(get_db),
 ):
@@ -51,6 +53,7 @@ async def get_timeline(
     if date_to:
         query = query.where(DailySession.session_date <= date_to)
 
+    query = query.limit(limit).offset(offset)
     result = await db.execute(query)
     events = result.scalars().all()
 
@@ -133,6 +136,8 @@ async def get_strike_events(
     log_date: date | None = None,
     date_from: date | None = None,
     date_to: date | None = None,
+    limit: int = 500,
+    offset: int = 0,
     current_user: User = Depends(get_current_user),
     db: AsyncSession = Depends(get_db),
 ):
@@ -152,6 +157,7 @@ async def get_strike_events(
     if date_to:
         query = query.where(func.date(StrikeEvent.occurred_at) <= date_to)
 
+    query = query.limit(limit).offset(offset)
     result = await db.execute(query)
     events = result.scalars().all()
     return [
@@ -192,6 +198,8 @@ async def list_logs(
     log_date: date | None = None,
     date_from: date | None = None,
     date_to: date | None = None,
+    limit: int = 500,
+    offset: int = 0,
     current_user: User = Depends(get_current_user),
     db: AsyncSession = Depends(get_db),
 ):
@@ -210,7 +218,7 @@ async def list_logs(
     if date_to:
         query = query.where(ActivityLog.log_date <= date_to)
 
-    result = await db.execute(query)
+    result = await db.execute(query.limit(limit).offset(offset))
     return result.scalars().all()