Detect unknown entity references in Template helpers (config-entry based)

[pos-ei-don]

Is your feature request related to a problem?

Spook's unknown_entity_references repairs cover automation, script, scene, lovelace (and group via unknown_members). They do not cover UI-created Template helpers (the template integration, config-entry based). There is no template ectoplasm at all.

The config-entry helpers that do have repairs (trend, utility_meter, switch_as_x, integration) only check a single source_entity via unknown_source.py — not multi-ref / template scanning.

Result: entity references inside Template helpers break silently. In my setup several were dead for months — Jinja state/availability templates and turn_on/turn_off action targets pointing at renamed/removed entities — and Spook never flagged them, while the same broken refs in automations were flagged.

Proposed approach (gauging interest before I open a PR)

A new ectoplasms/template/repairs/unknown_entity_references.py that iterates hass.config_entries.async_entries("template") and scans entry.options. The HA template config flow stores every entity-ref-bearing field through just two selector types:

• TemplateSelector (Jinja strings) → async_extract_entities_from_template_string
• ActionSelector (action sequences) → the recursive extract_entities_from_action_config already used by the automation repair

So a generic scan over entry.options.values() reuses Spook's existing extraction (incl. the proven service-name handling, all/none, template-aware filtering) — no per-helper-type field list needed. It would honor the usual automatically_clean_up_issues, skip disabled helpers, and filter this.* self-refs.

One open question for you

The cleanest way to map a template config entry → its entity_id / edit URL for the issue placeholders (registry lookup by config_entry_id?), since these helpers span many platforms and the entity object may not carry the raw config.

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Happy to do the implementation + tests (mirrored on the automation repair test) if you're open to it. Would you take such a PR?