fix: remove broken @aptos-labs/ace-sdk dependency

[maniapulai]

The @aptos-labs/ace-sdk@0.1.0 package is not available in the npm registry, causing installation failures.

Changes

• Removes the unavailable dependency from package.json
• Replaces ace-sdk implementations with placeholder functions that throw descriptive errors indicating the package is unavailable
• Updates both the main app and examples duplicate

Notes

These placeholder functions can be replaced with an alternative threshold encryption library or restored when the package becomes available in npm.

---

Note

Removes the unavailable @aptos-labs/ace-sdk and stubs out ACE-based greenBox logic to prevent install failures while keeping AES-GCM redBox encryption intact.

• Deletes @aptos-labs/ace-sdk from package.json and lockfile
• Replaces ACE committee/contract helpers and encryptRedKey/decryptGreenBox with placeholder functions that throw descriptive errors
• No changes to AES-GCM file encryption (generateRedKey, encryptFile, decryptFile)

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