A buffer failure on POST /api/v1/reports now returns 500 instead of a
false `ok`: the failure is server-side and a client can retry. An
over-limit body returns 413 (errors.As on `*http.MaxBytesError`);
malformed JSON stays 400. A MaxBodyBytes middleware (1 MiB) caps every
route; a route group can only lower that limit. The raw geo blob is no
longer logged, only its length; client_id, timestamp and decode error
text are length-bounded before logging. A decodeJSON handler helper is
added. Panic recovery routes the stack through slog as structured
JSON. Writing a report file now returns its error, so a failed final
flush fails the stop and the process exits non-zero.
Model: opus-5-5
Add ReadHeaderTimeout and IdleTimeout to the http.Server as named constants beside the existing timeouts. Add a SecurityHeaders middleware (HSTS, a JSON-API CSP of default-src 'none'; frame-ancestors 'none', X-Frame-Options DENY, nosniff, Referrer-Policy, Permissions-Policy), registered before CORS so preflight responses carry it. Resolve the client IP from X-Forwarded-For / X-Real-IP only when the direct peer is in the trusted-proxy allowlist (loopback plus RFC1918 by default, configurable via TRUSTED_PROXIES); an untrusted peer's forwarded headers are ignored. Uses net/netip; no new dependency.
Model: opus-4-8 (implementation and review); claude-fable-5 (merge)
Introduce the Go backend (netwatch-server) with an HTTP API that
accepts telemetry reports and persists them as zstd-compressed JSONL
files. Reports are buffered in memory and flushed to disk when the
buffer reaches 10 MiB or every 60 seconds.