* telemetry: persist server state across restarts
The telemetry server kept the instance map and Prometheus gauges only
in process memory, so every deploy or restart reset all collected
metrics until clusters re-reported over the next 24h.
Snapshot the instance map to a JSON state file (atomic tmp+rename) on
a debounced interval and on SIGTERM, and restore it on startup,
preserving received_at so the cleanup and active-cluster windows stay
correct. Defaults to data/telemetry-state.json, which the deployed
systemd unit's WorkingDirectory already provides; -state-file=''
disables.
* telemetry: keep instances for 90 days by default
With state now persisted across restarts, a longer retention default is
meaningful; raise -max-age from 30 to 90 days so per-cluster data
survives long enough for quarterly views.
* fix(telemetry): make server build reproducible with proper context and deps
* Update telemetry/server/go.mod: go version
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
* telemetry/server: optimize Dockerfile (organize cache deps, copy proto); run as non-root
* telemetry: update deployment docs for new Docker build context
* telemetry: clarify Docker build/run docs and improve Dockerfile caching
- DEPLOYMENT.md: specify docker build must run from repo root; provide full docker run example with flags/port mapping
- README.md: remove fragile 'cd ..'; keep instruction to run build from repo root
- Dockerfile: remove unnecessary pre-copy before 'go mod download' to improve cache utilization
---------
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
Chris Lu