rework configuration overview into a task oriented workflow, make...

General MR

Summary

Implemented the configuration-docs consolidation.

Key changes:

• Reworked the configuration overview docs/configuration/index.md into a task-oriented workflow.
• Made docs/configuration/base-config.md explicitly generated, with the schema identified as the exhaustive validation contract.
• Added the helm-docs template and generation/check script, targeting helm-docs v1.14.2.
• Added pre-commit and pre-push freshness checks in lefthook.yaml
• Documented the contributor workflow in CONTRIBUTING.md
• Corrected value annotations for registryCredentials, openshift, flux, and package sections in values.yaml

The sizable base-config.md deletion is expected generated churn: stale defaults and package versions were replaced, and undocumented rows are no longer presented as authoritative. No chart configuration was removed; values.schema.json remains the exhaustive key/type contract.

Relevant logs/screenshots

N/A

Linked Issue

Closes #3401 (closed)

Upgrade Notices

N/A