Terminology and identifier cleanup pass across operator UI

[alexeygrigorev]

Part of UX epic #67. From the operator UX audit (finding 12, MEDIUM — high impact on "feels technical").

Problem

Engineering identifiers leak into the UI: template key slugs shown as <code> (template_catalog.html:33, template_detail.html:9,35, transactional_queue.html:46); normalized_email as helptext under every email; enum leakage ("SNAPSHOTTING"); "Locked" as the campaign action for non-drafts (campaign_list.html:78).

Ask

Lead with human template name (key as muted secondary); drop redundant normalized_email where it equals the displayed email; replace "Locked" with "View"/blank; ensure no raw enum names surface.

Acceptance

• Template name leads over key.
• No redundant normalized_email helptext.
• No raw enum/"Locked" labels in list/detail views.
• Tests + lint pass.