Refresh library theme and interactive book previews

[waypointinstitute]

Summary

• retune the shared theme tokens and shelf styling to remove remaining brown wood tones and align the catalogue with the institute blue palette
• update the reusable book card to trim previews, expose an interactive cover toggle with clear cues, and improve accessibility labels for the flip interaction
• sync spotlight and search client renderers plus the global enhancement script so dynamically injected cards gain the new flip behaviour and aria attributes

Testing

• npm run lint (fails: TypeScript cannot resolve astro/tsconfigs/strict and fuse.js declarations in this environment)

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Codex Task