feat(phase-1): TapTrack Hub initial scaffold

Full project scaffold for TapTrack Hub — cloud SaaS control plane
for managing on-prem TapTrack school deployments.

## Infrastructure
- Docker Compose: backend (gunicorn+uvicorn), Celery worker + beat,
  frontend (Vite build + nginx), PostgreSQL 15, Redis 7, nginx proxy
- Dockerfile for backend and frontend, nginx reverse proxy config

## Backend (FastAPI + SQLAlchemy async + Celery)
Database schema (10 tables):
  hub_users, schools, licenses, sms_jobs, sms_credit_ledger,
  invoices, invoice_line_items, school_subscriptions,
  support_tickets, ticket_replies, audit_logs, announcements

Auth: JWT (python-jose) + bcrypt + role-based FastAPI dependencies
  (get_current_user, require_super_admin, require_school_admin)

Routers (11): auth, schools, licenses, sms, billing, tickets,
  users, dashboard, school_portal, announcements, sync

Celery tasks (6):
  sms.process_queue, billing.generate_monthly_invoices,
  billing.send_invoice_email, billing.check_overdue,
  license.check_expiry, reports.send_monthly_reports

Services: SMTP email helper (smtplib + Jinja2)
Seed script: creates super admin admin@taptrack.io

## Frontend (Vue 3 + Vite + Pinia + Tailwind CSS)
Router: 14 routes across super admin + school portal layouts
Stores: Pinia auth store with localStorage persistence
API client: full axios client for all backend endpoints
Layouts: AppLayout (super admin), PortalLayout (school), AuthLayout
Components: AppSidebar, PortalSidebar, SidebarItem, KpiCard,
  StatusBadge, ToastStack
Pages: Login, Dashboard, Schools, SchoolDetail, Licenses, SMS,
  Billing, Tickets, TicketDetail, Users, Announcements, 404
Portal pages: Overview, Billing, SMS Reports, Tickets, Profile

## PAUL Planning Files
- .paul/ROADMAP.md: full 15-phase roadmap with detailed scope
- .paul/STATE.md: current position, tech stack, architecture notes
- .paul/phases/01-setup/01-PLAN.md: complete Phase 1 plan (done)
- .paul/phases/02 through 15: README stubs for all future phases

backend/app/models/audit.py

@@ -0,0 +1,21 @@
+import uuid
+from datetime import datetime, timezone
+from sqlalchemy import String, DateTime, ForeignKey, Text, JSON
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+from app.database import Base
+
+class AuditLog(Base):
+    __tablename__ = "audit_logs"
+
+    id: Mapped[str] = mapped_column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
+    school_id: Mapped[str | None] = mapped_column(String(36), ForeignKey("schools.id", ondelete="SET NULL"), nullable=True, index=True)
+    actor_id: Mapped[str | None] = mapped_column(String(36), nullable=True)
+    actor_email: Mapped[str | None] = mapped_column(String(255), nullable=True)
+    action: Mapped[str] = mapped_column(String(100), nullable=False, index=True)
+    entity_type: Mapped[str | None] = mapped_column(String(50), nullable=True)
+    entity_id: Mapped[str | None] = mapped_column(String(36), nullable=True)
+    detail: Mapped[dict | None] = mapped_column(JSON, nullable=True)
+    ip_address: Mapped[str | None] = mapped_column(String(45), nullable=True)
+    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=lambda: datetime.now(timezone.utc), index=True)
+
+    school: Mapped["School | None"] = relationship("School", back_populates="audit_logs")