feat: Phase 1 scaffold — frontend canvas + backend skeleton

Frontend:
- Vite + React 18 + TypeScript + Tailwind v4 + Shadcn/ui
- React Flow v12 canvas with all 11 node types and 5 edge types
- Dark theme with project design system (cyan, green, orange, purple accents)
- Collapsible sidebar, toolbar, detail panel
- Zustand store for canvas state
- Demo data with 10 nodes and 10 edges

Backend:
- FastAPI + SQLAlchemy async + SQLite (Python 3.13)
- DB models: Node, Edge, CanvasState, PendingDevice, ScanRun
- REST API routes: auth, nodes, edges, canvas, scan, status (WebSocket)
- JWT auth + bcrypt via config.yml
- Pydantic v2 schemas

Infra:
- GitHub Actions quality + security workflows
- .gitignore, .env.example, verify-tooling.sh, security-check.sh

backend/app/schemas/scan.py

@@ -0,0 +1,30 @@
+from datetime import datetime
+from typing import Any
+
+from pydantic import BaseModel
+
+
+class PendingDeviceResponse(BaseModel):
+    id: str
+    ip: str
+    mac: str | None
+    hostname: str | None
+    os: str | None
+    services: list[Any]
+    suggested_type: str | None
+    status: str
+    discovered_at: datetime
+
+    model_config = {"from_attributes": True}
+
+
+class ScanRunResponse(BaseModel):
+    id: str
+    status: str
+    ranges: list[str]
+    devices_found: int
+    started_at: datetime
+    finished_at: datetime | None
+    error: str | None
+
+    model_config = {"from_attributes": True}