feat: reports page backend integration (threats, hazards, risks)

[Varunreddy2k03]

What this does

Replaces static/mock report cards with real backend data.

Changes

• ReportsPage.jsx — loads threats, hazards, risks via Promise.all on mount
• ReportPDF.jsx — print-ready PDF modal triggered by ↓ PDF button
• services/phoenixApi.js — shared API helpers (getThreats, getHazards, getRisks, etc.)

Features

• Loading, empty, and error states
• Handles both paginated (response.items) and flat array responses
• PDF download via window.print() with print stylesheet
• All requests via /api proxy — no hardcoded backend URLs

Not changed

• Login untouched
• Backend untouched
• No other team members' files modified