Cleaning up after our own changes, not pre-existing dead keys.
- gallery.feedback.* (10 keys) -- StoryFeedbackSheet was their only consumer
and it was removed in 3ef4bd8c as an unreachable duplicate of the lightbox.
- cssTemplates.title and settings.moderation.wordFilters -- orphaned by
b80ce73e, which removed the component-side heading on the tabs that rendered
a heading identical to the shell's.
- settings.analytics.customCspWarningText -- superseded by
customOnlyCspWarningText in 9251745a, which was deliberately a new key so the
stale pre-proxy string could not win over the new inline default. The sibling
customCspWarning title is still in use and stays.
Each verified to have zero t() references in src before removal. Key-diff
against HEAD: en/de -13, the six partial locales -12 (they never had
customCspWarningText), 0 changed and 0 added in any of the eight.
removeUnusedKeys is false by design, so this had to be a deliberate pass.