10. Feature: Add Protocol Diagnostics page

[smithaldon1]

Parent Epic

#206

Purpose

Add a FIP Protocol Diagnostics page modeled on Demo-Factory, backed by FIP connection and health APIs.

Acceptance Criteria

• Shows cards for OPC-UA, MQTT, BACnet, API, and ingestion health where available.
• Shows configured connection status, last test result, and readable errors.
• Includes a searchable protocol/tag mapping table.
• Uses FIP API data, not hardcoded Demo-Factory state.
• Includes troubleshooting commands or next steps for local Demo-Factory validation.

Implementation Order

Step 10. Depends on connection API, test endpoint, and at least one adapter foundation.

Test Plan

Frontend tests for empty/healthy/error states and Playwright coverage for diagnostics rendering.