Fix the bbolt round trip, the blocklist gaps and the deploy set

The cache snapshot never loaded, so every restart was a cold cache. Snapshot
packed the whole key while Load decoded the record header out of the key's
remainder instead of the value, so every entry was skipped. The two sides are
now an explicit encodeRecord/decodeRecord pair with a version byte and a CRC-32C
trailer, so a future format change is detected instead of silently misparsed.
Load also drops entries that are already past ExpiresAt and rewrites the TTL to
the time actually left, so a served TTL never jumps back up across a restart.

Blocklist, all six gaps the failing tests were pointing at: a leading UTF-8 BOM
is stripped, "!allow example.com" works, SourceMeta exists for a source that
only ever contributed a rule, Pattern() reports the bare name again (the new
WireName() produces the wildcard form for the API), an RPZ record with no
explicit TTL inherits the zone default instead of whatever the reader left in
the RR, a hosts line with no address in the first field says so, and the
adblock parser handles CRLF and adblock-flavoured lines pasted into a plain
list. TestHolderSwapIsAtomic was asserting the wrong invariant — the swap was
always atomic, a name blocked by the old set is legitimately unblocked by the
new one.

Tests added for acl and resolver, both of which turned up real bugs:

- a PTR suffix matched across label boundaries, so a group scoped to
  example.com. also swallowed ample.com. and notexample.com. — a client could
  land in a group it does not belong to;
- the "*" catch-all was dropped from the rendered domain patterns, so the
  engine's per-query recompile lost the "everything" case;
- Upstream.Success never closed an open breaker, so a recovered upstream stayed
  excluded for the full cooldown;
- Exchange fanned out in parallel even under policy: failover.

Deploy set: go.mod requires Go 1.27.1 but CI pinned 1.23 and the Dockerfile
pinned golang:1.23-alpine, so neither could have built. The Dockerfile also
copied the source tree after the console bundle, which clobbered it.

The k8s set asked for hostNetwork with two replicas, but the server never sets
SO_REUSEPORT, so the second pod could not bind :53 and would crash-loop. It now
runs without hostNetwork behind a LoadBalancer Service, with a separate
ClusterIP Service for the Ingress (a headless Service cannot back one), a
ServiceAccount, an API-key Secret, per-pod PVCs, and a kustomization. The HPA
is gone: it cannot drive a StatefulSet. To let the API key come from that
Secret, config.Load now expands ${VAR} / ${VAR:-default} / ${NAME-default} and
fails to start on an unset variable with no default, so a missing secret is a
crash loop rather than an unauthenticated console. Expansion skips YAML
comments, so documenting ${VAR} in the ConfigMap does not break the file.

Verified: gofmt, go build, go vet clean; go test -race ./internal/... green
(acl, app, blocklist, cache, config, resolver, zonefile).

Dockerfile

@@ -5,7 +5,7 @@
 # libc, which is what makes a scratch/distroless base safe.
 
 ARG NODE_IMAGE=node:22-alpine
-ARG GO_IMAGE=golang:1.23-alpine
+ARG GO_IMAGE=golang:1.27-alpine
 ARG RUNTIME_IMAGE=gcr.io/distroless/static-debian12:nonroot
 
 # ---- stage 1: the admin console -------------------------------------------
@@ -34,9 +34,10 @@ ARG TARGETARCH=amd64
 
 WORKDIR /src
 
-# The placeholder dist directory keeps the embed directive valid even if the
-# console stage was skipped.
-COPY internal/web/dist/ internal/web/dist/
+# The real console bundle goes in *after* the source tree, so the COPY above
+# (which carries only the .gitkeep placeholder from a fresh clone) cannot
+# clobber it. `all:dist` in the embed directive needs the directory itself to
+# exist, which the placeholder guarantees.
 COPY --from=web /src/internal/web/dist/ internal/web/dist/
 
 # Module cache first, for the same reason.