feat: ship n2k-native streams and richer source diagnostics

[jakthom]

Summary

• emit the software-consumer envelope as exactly three top-level keys: verbatim native n2k payload, Beacon-owned metadata, and top-level raw CAN bytes
• upgrade github.com/open-ships/n2k to v1.0.0 and preserve the complete Go struct payload across MQTT, SSE, WebSocket, TCP, files, and buffers
• add source and sink stream inspectors with server-side CEL filtering, live filter updates, JSONL/CAN views, exact large-integer preservation, copy/export, field-to-CEL suggestions, and uncapped capture totals with a latest-200 display buffer
• consolidate source metrics terminology and add richer per-device/PGN traffic diagnostics in the UI
• add local hot-reload support and set the release baseline to 1.1.0

Breaking change

The consumer wire contract intentionally changes to {\"payload\": ..., \"metadata\": ..., \"raw\": ...}. This is a net-new product, so no compatibility shim is included.

Validation

• test -z \"$(gofmt -l .)\"
• git diff --check
• go test ./... -timeout 300s
• go vet ./...
• CGO_ENABLED=0 go build ./...
• npm test (4 Playwright tests passed)