Address CodeRabbit findings on PR #36:
1. The previous patch attached `QDRANT_API_KEY` as an `api-key` header
regardless of URL scheme, which would leak the secret on the wire if
a user configured an authenticated Qdrant over plain HTTP. Add a
guard that rejects the combination and throws a specific error,
placed before the readiness probe so its message is not masked by
the generic "Cannot reach external Qdrant" handler. Loopback URLs
(`localhost`, `127.0.0.1`, `[::1]`) are accepted on `http://` so
local-dev workflows where users run authenticated Qdrant on plain
HTTP keep working. The URL is parsed (rather than checked with
startsWith) so hostnames like `http://localhost.evil.com` are not
mistaken for loopback.
2. The "omits api-key header when QDRANT_API_KEY is not set" test
relied on the spread of the real `constants.js` module, which means
it would flake to a header-attached state on any developer machine
with `QDRANT_API_KEY` exported in the shell. Pass
`QDRANT_API_KEY: undefined` explicitly so the override always wins.
3. Add two tests covering the new guard: one asserting the rejection
on plain HTTP for non-loopback hosts, and one asserting that the
localhost exception still attaches the api-key header.
4. Document the HTTPS requirement (and localhost exception) in the
`QDRANT_API_KEY` row of the README configuration table.
External Qdrant deployments that require authentication (notably Qdrant Cloud,
which returns 403 on every endpoint including /healthz without an api-key
header) cannot pass the existing readiness check, so codebase_index fails with
"Cannot reach external Qdrant" even though codebase_health and codebase_search
still succeed -- their qdrant-js client paths attach the key automatically.
Forward QDRANT_API_KEY as an `api-key` request header from
ensureExternalQdrantReady() by extending waitForService() with an optional
RequestInit. Docker-managed and unauthenticated external Qdrant deployments
remain unaffected (no init forwarded -> no headers).
Covered by two new unit tests in docker.test.ts.
Giancarlo Erra