refactor: replace i18n HTTP requests with build-time bundling

[keithwillcode]

Refactor i18n system to use build-time bundling and eliminate runtime HTTP requests

Summary

This PR refactors the i18n system to eliminate runtime HTTP requests for translation files, which were causing 60-second timeouts in production. The key changes include:

• Build-time bundling: Replaced runtime HTTP requests with direct file system reads using a new translationBundler.ts
• Eliminated circular dependencies: Moved translation files from apps/web/public/static/locales/ to packages/lib/server/locales/ so packages don't need to reach into the web app
• Maintained cache invalidation: Uses CalComVersion for cache busting similar to the frontend pattern
• Preserved build compatibility: Added copy-locales-static.js script to copy files to public folder during build
• Serverless optimization: Only loads the specific locale requested instead of all locales upfront

The refactor maintains backward compatibility while significantly improving performance and eliminating the HTTP timeout issues.

Review & Testing Checklist for Human

This is a high-risk architectural change that requires thorough testing:

• Test translation loading in different locales (en, es, fr, de, etc.) and verify all translations display correctly
• Verify build process works correctly by running yarn build and checking that locale files are copied to apps/web/public/static/locales/
• Test in production environment to ensure path resolution works correctly in serverless/deployed contexts
• Check for missed import references by searching codebase for any remaining references to old translation paths
• Verify cache invalidation by changing CALCOM_VERSION and confirming translations update properly

Recommended test plan: Deploy to staging environment and test booking flows in multiple languages, especially the ones that were previously timing out.

---

Diagram

%%{ init : { "theme" : "default" }}%%
graph TD
    subgraph "Translation Loading Flow"
        A["packages/lib/server/i18n.ts"]:::major-edit
        B["packages/lib/server/translationBundler.ts"]:::major-edit
        C["packages/lib/server/locales/{locale}/common.json"]:::major-edit
        D["apps/web/scripts/copy-locales-static.js"]:::major-edit
        E["apps/web/public/static/locales/{locale}/common.json"]:::context
        F["apps/web/package.json build script"]:::minor-edit
    end
    
    subgraph "Updated Import Paths"
        G["packages/platform/atoms/vite.config.ts"]:::minor-edit
        H["apps/api/v2/next-i18next.config.js"]:::minor-edit
        I["Multiple booking pages"]:::minor-edit
    end
    
    A -->|"dynamic import"| B
    B -->|"readFileSync"| C
    D -->|"copies during build"| E
    F -->|"runs copy-static"| D
    G -->|"updated alias"| C
    H -->|"updated localePath"| C
    I -->|"updated imports"| A
    
    subgraph Legend
        L1[Major Edit]:::major-edit
        L2[Minor Edit]:::minor-edit
        L3[Context/No Edit]:::context
    end
    
    
    classDef major-edit fill:#90EE90
    classDef minor-edit fill:#87CEEB
    classDef context fill:#FFFFFF

Loading

Notes

• Session: Requested by Keith Williams (@keithwillcode) - Devin session
• Performance impact: This should significantly reduce server response times by eliminating 60-second HTTP timeouts
• Breaking change risk: While designed to be backward compatible, the architectural change from HTTP requests to file system reads could behave differently in various deployment environments
• Merge conflicts resolved: Used Benny's safer 2-step approach to integrate latest translations from main branch
• All CI checks passing: 35 pass, 0 fail - including all E2E test suites that were previously failing due to translation loading issues

[devin-ai-integration]

🤖 Devin AI Engineer

I'll be helping with this pull request! Here's what you should know:

✅ I will automatically:

• Address comments on this PR that start with 'DevinAI'.
• Look at CI failures and help fix them

Note: I can only respond to comments from users who have write access to this repository.

⚙️ Control Options:

• Disable automatic comment and CI monitoring

[vercel]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

2 Skipped Deployments

Name	Status	Preview	Comments	Updated (UTC)
cal	⬜️ Ignored (Inspect)	Visit Preview		Jul 12, 2025 7:32am
cal-eu	⬜️ Ignored (Inspect)	Visit Preview		Jul 12, 2025 7:32am

[delve-auditor]

✅ No security or compliance issues detected. Reviewed everything up to c1e0018.

Security Overview

• 🔎 Scanned files: 64 changed file(s)

Detected Code Changes

Change Type	Relevant files
Configuration changes	► next-i18next.config.js     Update locale path ► next.config.js     Update translation import path ► i18n.json     Update locale path configuration
Refactor	► i18n.ts     Refactor translation loading mechanism ► translationBundler.ts     Add new translation bundling system ► copy-locales-static.js     Add script for copying locale files
Enhancement	► Move all locale files from /apps/web/public/static/locales to /packages/lib/server/locales     Centralize translation files location

Reply to this PR with @delve-auditor followed by a description of what change you want and we'll auto-submit a change to this PR to implement it.

[github-actions]

E2E results are ready!

• Workflow #67253.1 latest results

[cubic-dev-ai]

cubic found 5 issues across 58 files. Review them in cubic.dev

_{React with 👍 or 👎 to teach cubic. Tag @cubic-dev-ai to give specific feedback.}