Ship persistent twelve-theme collection

[erickkkyt]

Summary

• replace the four early study themes with the 12-theme launch collection
• feature Satoru Gojo first and add paired background/marketing assets to the README
• add persistent install/switch/pause/resume/update lifecycle and safe restore
• keep the right summary rail visibly themed across renderer updates

Verification

• pnpm release:check
• 34 test files / 248 tests
• 12 theme packages validated
• TypeScript and production Gallery build passed
• live Codex Desktop 26.715.21425 verification recorded

Repository remains private for owner review.