feat(proxy-ui): ONOS-style SVG topology and visual Instance detail dashboard (Closes #126)

[zhy1658858023]

Motivation

• Replace the simplistic text/div topology with a stable, responsive SVG topology and upgrade the Instance detail view into a visual, operator-friendly dashboard while preserving existing polling, selection and accessibility semantics.
• Keep the change incremental, avoid new front-end frameworks or build tooling, and rely only on native HTML/CSS/JS and the existing Proxy APIs.

Description

• Implemented a deterministic topology model and layout via buildTopologyModel() and computeTopologyLayout() and render an inline responsive SVG in renderSystemTopology() with inline <symbol> icons for Scheduler/Proxy/Instance, animated links, accessibility attributes, keyboard selection and event-delegated click handling (files modified: UI/proxy_ui/static/app.js, UI/proxy_ui/static/style.css).
• Reworked Instance Detail into KPI cards, resource metric bars, memory/GPU donut charts, queue/load visualizations and structured hardware cards, plus a collapsed details Raw JSON with a Copy JSON button, and preserved the hash-based selectedInstanceId flow (changes in UI/proxy_ui/static/app.js).
• Added robust, defensive helpers for numeric formatting and bounds: finiteNumber(), percentOf(), displayNumber(), renderMetricBar(), renderDonutChart() and extractQueueMetrics() which safely detect queue-like numeric fields from load, resource, meta, queue(s), stats without inventing values; donuts/bars show No data or — for missing or invalid totals.
• Styling additions include topology CSS variables, responsive SVG container, link animation with prefers-reduced-motion support and paused-animation behavior; no backend API changes were made; new test fixture UI/proxy_ui/test_proxy_ui_pure.js exercises pure functions and layout determinism.

Testing

• Ran static/functional pure-JS tests: node --check UI/proxy_ui/static/app.js and node UI/proxy_ui/test_proxy_ui_pure.js, and they passed (tests validate topology model/layout, percent/donut handling, queue extraction and theme/reduced-motion hooks).
• Verified server module compiles: python3 -m py_compile UI/proxy_ui/proxy_ui_server.py succeeded.
• Note: UI screenshots were not produced because no browser/runtime (Chromium/Playwright) was available in this environment; the PR documents the visual states and the topology/detail behavior and can be validated locally by running the Proxy UI against live or fixture Proxy payloads.

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Codex Task