Constant FLUX_KEY_CHART 

pub const FLUX_KEY_CHART: &str = "chart";

Canonical Flux v2 per-HelmRelease inline-chart-template container-axis key every caixa-flux-emitted HelmRelease document nests its per-CR chart-template block under (spec.chart on HelmRelease) — the Flux v2 CRD schema places the HelmChartTemplate sub-document (whose nested spec.chart string names the referenced chart, spec.sourceRef names the source-of-truth (kind, name, namespace) triple, and spec.interval names the per-CR reconcile cadence) under this single container key, so drift on the container axis silently dangles the whole chart-template block the Flux v2 helm-controller’s per-CR reconcile loop reads to source the referenced chart at Helm-render time (a "Chart" / "chartTemplate" / "helmChart" / "chartRef" typo at either the emit-side format-string template or a downstream test- fixture probe silently dangles the HelmRelease.spec.chart chart- template resolution at the Flux v2 helm-controller’s CRD registration; the referenced chart never resolves, and the per-Servico workload freezes at apply time with no field naming the container-axis-drift root cause).

The single source of truth the rendered Flux bundle’s per-CR chart-template-container-axis-naming reaches for:

• the rendered helmrelease.yaml document’s per-HelmRelease spec.chart block (caixa-flux/src/lib.rs — the cluster_bundle helmrelease format-string template’s baked chart:\n container axis at line 914, sibling to the peer lifted FLUX_KEY_SOURCE_REF source-reference container axis nested inside the same block + FLUX_KEY_VALUES per-cluster-override block-body axis at the sibling spec.values position);
• two test-side navigation sites in mod tests that probe the rendered helmrelease.yaml document’s .get("chart") container axis to reach the nested spec.chart.spec.sourceRef.kind pin against the sibling lifted FLUX_KIND_GIT_REPOSITORY axis (caixa-flux/src/lib.rs:2680, 2774).

The container-axis key names the same Flux-v2-helm-controller-side per-HelmRelease chart-template container as the peer sibling per-CR source-reference container-axis FLUX_KEY_SOURCE_REF nests under, and must move together on any future Flux v3 rebrand (a hypothetical upstream Flux v3 rename of the per-HelmRelease chart-template container axis from chart to Chart / chartTemplate / helmChart / chartRef, coordinated with the upstream fluxcd/flux2 project’s per-version deprecation cycle, would land at this one const rather than scattered across the one per-CR format-string template + two per-test-fixture probe sites).

The PRIME DIRECTIVE duplication-budget rule (THEORY.md §I.3.5, “every recurring shape becomes a generator before it becomes a pattern; every pattern becomes a library before it becomes duplicated code. The duplication budget is zero.”) promotes the constant to a typed substrate-side &'static str on the same trajectory the FLUX_KEY_SOURCE_REF (e985089) / FLUX_KEY_VALUES (b54dc87) lifts established on the sibling canonical-Flux-v2-per-HelmRelease-body-key surfaces — completes the triplet of Flux v2 per-HelmRelease spec.* body-key constants (spec.chart + spec.chart.spec.sourceRef + spec.values) the cluster_bundle renderer’s helmrelease.yaml format-string template threads through its per-CR block-body layout.

The inner scalar-value axis spec.chart.spec.chart (the chart-name leaf the HelmChartTemplate.spec sub-document mounts under; the same spelling "chart" at a distinct schema position) is a schematically separate leaf-scalar-key axis (the chart-NAME field the helm-controller resolves through the sibling FLUX_KEY_SOURCE_REF triple’s source), and is not covered by this lift — a rebrand of the container axis (spec.chart in this const) does not necessarily coincide with a rebrand of the leaf-scalar spec.chart.spec.chart chart-name field key, so the two axes stay decoupled at the substrate.