Add TypeScript Express backend with love story APIs

[Fstarnb]

Summary

• add a TypeScript Express server with endpoints for hero banner, stats, memories uploads, chat replies, game cards, and love-letter content
• configure project tooling with package.json, tsconfig, and gitignore entries for node artifacts and uploads
• document how to run the backend and the available API surface in the README

Testing

• npm install (fails: npm registry returned 403 for @types/express in this environment)

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Codex Task

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Add missing CORS type definitions

TypeScript imports cors but package.json does not declare @types/cors, so running npm run build (tsc) or npm run dev (ts-node) will error with TS7016 that it cannot find declarations for cors, blocking both the compiled and dev server entrypoints; include the type package or adjust the import to restore builds.

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