Related to

Epic: #6051
Policy: docs/policies/breaking-changes.md

Outcome

Deprecate (warning only, no removal) every application-config proxy Helm value in chart 8.10, guiding operators to the component's extraConfiguration.

• Add a camundaPlatform.keyDeprecated soft-warning helper (mirrors keyRemoved but warns instead of failing), naming the replacement and the removal version (8.11).
• Emit a per-key [camunda][warning] DEPRECATION via NOTES.txt, fired only when the user set a non-default value.
• No key is removed; rendered manifests are unchanged. Both the legacy values and extraConfiguration work during the deprecation window.
• Hub-bound keys gate on both the legacy and camundaHub.* namespaces.

Acceptance

• make helm.lint and make go.test pass (warnings render in NOTES only; no golden changes).
• helm install --dry-run shows the DEPRECATION line only when a deprecated key is set to a non-default value, and nothing on defaults.
• helm template output is byte-identical vs. baseline.