feat(topology): force-directed mesh graph from NEIGHBORINFO and TRACEROUTE

[iceice400]

Summary

• Extend GET /api/analytics/topology?hours=24 — returns { nodes, edges, routes } from NEIGHBORINFO + TRACEROUTE (last 500 NI / 100 route packets)
• New Topology sidebar tab with D3 force-directed graph (node size = packet count, colour = protocol)
• Weak links (RSSI < -110 dBm) shown dashed; click node highlights TRACEROUTE path edges
• Map topology overlay updated for new API response shape

Why

Operators need a mesh link view beyond the map polylines. Reuses decoded NEIGHBORINFO/TRACEROUTE already in SQLite — read-only, no relay/TX impact.

Type

• Bug fix
• Feature
• Docs
• Refactor
• UI
• Installer
• Region support
• Hardware change

Testing

• Local unit tests
• Tested on hardware
• Dashboard tested on device

python -m unittest tests.test_topology_api -v

Manual checklist (on gateway with NEIGHBORINFO traffic):

1. Sidebar → Topology → graph renders with ≥10 nodes on busy mesh
2. Toggle 1h / 6h / 24h — counts and edges refresh
3. Weak links (< -110 dBm) appear dashed/grey
4. Click node → TRACEROUTE path edges highlight cyan
5. Dashboard map → Topology Links overlay still works
6. Confirm no relay/TX behaviour change

Hardware: RAK7248 or Pi + HAT · US915 mesh with NEIGHBORINFO

Impact

• Parsing
• Relay
• TX
• Radio driver
• Region logic
• UI + read-only API
• Installer only

Risks: Low — read-only SQL; edge query capped at 500 packets. D3 loaded from CDN (same pattern as Chart.js).

AI-assisted?

• Yes