Scaffold Phase 0: agent -> Redpanda -> ingest -> ClickHouse -> api -> web

End-to-end log pipeline for Linux hosts, per /docs/architecture.md:

- proto: shared gRPC contract (agent <-> ingest), Go bindings checked in
- agent: Rust, musl-targeted, journald/file sourcing, RFC5424 parser,
  mTLS gRPC client, no required config for the common case
- ingest: Go, single binary with --mode server|consumer|all; gRPC front
  end forwards to Redpanda unchanged, consumer normalizes and
  batch-writes to ClickHouse with at-least-once delivery
- storage: ClickHouse schema + a plain SQL-file migration runner
- api: minimal SELECT-only query endpoint, plain REST (not gRPC+gateway
  yet -- see api/README.md)
- web: SvelteKit static SPA, one query page
- transport: Redpanda compose + topic provisioning
- cli: sentryctl ping stub
- hack/dev-certs: throwaway CA + cert generation for local mTLS
- root docker-compose.yml + docs/phase-0-runbook.md tie it together

Not yet run end-to-end against real Docker/ClickHouse/Redpanda -- see the
runbook's caveats section before relying on this working as-is.

hack/README.md

@@ -0,0 +1,16 @@
+# hack
+
+Local developer tooling that isn't part of any shipped component — scripts
+you run against your own machine/dev stack, not code that ends up in a
+container image (except `dev-certs`' *output*, which mounts into the
+ingest container).
+
+Not one of the top-level directories in the original monorepo scaffold —
+added because dev-only mTLS cert generation didn't have a natural home in
+`/deploy` (real deployment manifests), `/transport`, or any other existing
+component. `/hack` is the conventional name for this in a lot of larger Go
+monorepos (Kubernetes among them).
+
+- `dev-certs/` — generates a throwaway CA + server/client cert pair for
+  local mTLS between the agent and ingest. See `/docs/phase-0-runbook.md`
+  for when to run it.