Get off Docker Hub, add a catalog values passthrough, fix the dind prune

Docker Hub rate-limits anonymous pulls per source IP and every node here
shares one NAT address, so a busy afternoon fails an unrelated build with
`toomanyrequests`. Nothing in this repo needs to be there.

Every base image now comes from mirror.gcr.io (python, alpine/helm,
postgres) or ghcr.io (uv, trivy). Verified digest-for-digest against
Docker Hub before switching, including the superseded postgres digest
this repo still pins, so every existing pin stays valid — same bytes,
different transport.

catalog.yaml: the three bitnami entries named `bitnamilegacy/<chart>`, a
repo alias nothing in the worker image configures, so they could never
resolve at provision time. All five entries are now `oci://` refs, which
need no `helm repo add`, and all are on latest stable:

  elasticsearch 21.3.15 -> 22.1.6     redis    20.6.2 -> 27.0.15
  postgresql    16.4.5  -> 18.8.0     podinfo  6.7.1  -> 6.14.0

Moving the chart pull is only half of it, though: a bitnami chart
defaults its own images to registry-1.docker.io. CatalogEntry gains a
`values:` dict, merged under the size's replicas and resources, so an
entry can set `global.imageRegistry` and move the image pull too. Size
wins on conflict — otherwise an entry setting replicaCount would make
every size deploy the same shape. Deep merge, because a shallow one
drops sibling keys of a shared nested map.

Bitnami charts reject a substituted registry unless
`global.security.allowInsecureImages` is set. That check is about
provenance, and the mirror serves byte-identical manifests, so it is set
deliberately and only for entries whose digests were verified.

The dind prune had `--filter until=168h` on both prunes, and it got both
cases exactly backwards. `until` reads an image's CREATED time, so it
deleted trivy every leg (a released tool image is always older than any
window) while protecting the dangling build layers it existed to remove.
Measured on node0: 21 dangling images / 5.96GB, and exactly 1 of them
older than 168h. Trivy is protected by a tag now, so the image prune
drops the filter; buildx keeps it, where age genuinely matters.

Tests: +10 unit (deep merge, precedence, no-mutation, and a guard that
fails if any catalog entry points at Docker Hub). Both new guards were
control-tested by breaking the code and watching them fail. The API test
that hardcoded `21.3.15` now reads the catalog — its subject is where
the value comes from, not what it is.

tests/unit/test_values.py

@@ -0,0 +1,102 @@
+"""What reaches `helm --values`: the catalog entry's values, with the size on top."""
+
+from __future__ import annotations
+
+from datetime import UTC, datetime
+from typing import Any
+from uuid import uuid4
+
+import pytest
+
+from services.worker.handlers import HandlerError, _deep_merge, _values_for
+from svcforge_core.domain.models import CatalogEntry, Instance, SizeSpec
+from svcforge_core.domain.states import InstanceState
+
+RESOURCES: dict[str, Any] = {"requests": {"cpu": "10m", "memory": "16Mi"}}
+
+
+def _entry(values: dict[str, Any] | None = None, replicas: int = 1) -> CatalogEntry:
+    return CatalogEntry(
+        service_type="redis",
+        chart="oci://mirror.gcr.io/bitnamicharts/redis",
+        chart_version="27.0.15",
+        sizes={"small": SizeSpec(replicas=replicas, resources=RESOURCES)},
+        values=values or {},
+    )
+
+
+def _instance(size: str = "small") -> Instance:
+    now = datetime.now(UTC)
+    return Instance(
+        id=uuid4(),
+        team="acme",
+        service_type="redis",
+        size=size,
+        state=InstanceState.REQUESTED,
+        namespace="tenant-acme",
+        release_name="acme-redis-0f8b7d3e",
+        chart_version="27.0.15",
+        created_at=now,
+        updated_at=now,
+    )
+
+
+# --------------------------------------------------------------------------- the merge
+
+
+def test_deep_merge_keeps_both_sides_of_a_shared_nested_key() -> None:
+    """The reason this is not `base | override`.
+
+    A shallow merge replaces the whole `global` map and silently drops imageRegistry, so
+    the pod pulls from a registry nobody chose.
+    """
+    merged = _deep_merge(
+        {"global": {"imageRegistry": "mirror.gcr.io"}},
+        {"global": {"storageClass": "longhorn"}},
+    )
+    assert merged == {"global": {"imageRegistry": "mirror.gcr.io", "storageClass": "longhorn"}}
+
+
+def test_deep_merge_override_wins_on_a_scalar() -> None:
+    assert _deep_merge({"a": 1}, {"a": 2}) == {"a": 2}
+
+
+def test_deep_merge_does_not_mutate_its_inputs() -> None:
+    """The catalog is loaded once at startup and shared by every provision.
+
+    Mutating `entry.values` here would leak one instance's size into the next one's values,
+    and the second tenant would get the first tenant's replica count.
+    """
+    base = {"global": {"imageRegistry": "mirror.gcr.io"}}
+    _deep_merge(base, {"global": {"storageClass": "longhorn"}, "replicaCount": 3})
+    assert base == {"global": {"imageRegistry": "mirror.gcr.io"}}
+
+
+# --------------------------------------------------------------------------- what helm gets
+
+
+def test_entry_values_reach_helm() -> None:
+    values = _values_for(_instance(), _entry({"global": {"imageRegistry": "mirror.gcr.io"}}))
+
+    assert values["global"] == {"imageRegistry": "mirror.gcr.io"}
+    assert values["replicaCount"] == 1
+    assert values["resources"] == RESOURCES
+
+
+def test_size_beats_entry_values() -> None:
+    """An entry that sets replicaCount must not override the size the tenant asked for.
+
+    Without this ordering every size deploys the same shape, and `medium` is a lie.
+    """
+    entry = _entry({"replicaCount": 99}, replicas=3)
+
+    assert _values_for(_instance(), entry)["replicaCount"] == 3
+
+
+def test_entry_without_values_is_unchanged() -> None:
+    assert _values_for(_instance(), _entry()) == {"replicaCount": 1, "resources": RESOURCES}
+
+
+def test_unknown_size_raises() -> None:
+    with pytest.raises(HandlerError, match="not in catalog"):
+        _values_for(_instance(size="enormous"), _entry())