Fix share view and protected sharing links

[kiyarose]

This patch tightens the public share experience and the AI summary prompt.

• Restores sentiment-based card highlighting in the shared view.
• Lets viewers expand each shared entry inline to read the full details.
• Enables full details by default for the family and professional presets.
• Adds an optional narrative overview generator to the shared view when weekly AI is enabled.
• Makes overview summaries objective in the worker by ignoring reader context and removing direct address / name usage.
• Hides the normal app shell, navigation, character, stickies, and score overlays on public share routes.
• Adds protected permanent share links at /share/<uid> with a viewer code gate and owner renewal period.
• Shows a styled unavailable page for revoked or expired share links instead of leaving the viewer on a loading state.
• Merges the existing kr/sharepatch1 push cron lint fix into the unified branch.
• Bumps Mentell to 1.12.0 for the new protected sharing flow.

Resolves #18