Move blockchain app READMEs to centralized documentation

- Relocate blockchain-event-bridge README content to docs/apps/blockchain/blockchain-event-bridge.md
- Relocate blockchain-explorer README content to docs/apps/blockchain/blockchain-explorer.md
- Replace app READMEs with redirect notices pointing to new documentation location
- Consolidate documentation in central docs/ directory for better organization

apps/zk-circuits/README.md

@@ -1,170 +1,9 @@
-# AITBC ZK Circuits
+# ZK Circuits
 
-Zero-knowledge circuits for privacy-preserving receipt attestation in the AITBC network.
+**Documentation has moved to:** [docs/apps/crypto/zk-circuits.md](../../docs/apps/crypto/zk-circuits.md)
 
-## Overview
+---
 
-This project implements zk-SNARK circuits to enable privacy-preserving settlement flows while maintaining verifiability of receipts.
+This file has been migrated to the central documentation location. Please update your bookmarks and references to point to the new location.
 
-## Quick Start
-
-### Prerequisites
-
-- Node.js 16+
-- npm or yarn
-
-### Installation
-
-```bash
-cd apps/zk-circuits
-npm install
-```
-
-### Compile Circuit
-
-```bash
-npm run compile
-```
-
-### Generate Trusted Setup
-
-```bash
-# Start phase 1 setup
-npm run setup
-
-# Contribute to setup (run multiple times with different participants)
-npm run contribute
-
-# Prepare phase 2
-npm run prepare
-
-# Generate proving key
-npm run generate-zkey
-
-# Contribute to zkey (optional)
-npm run contribute-zkey
-
-# Export verification key
-npm run export-verification-key
-```
-
-### Generate and Verify Proof
-
-```bash
-# Generate proof
-npm run generate-proof
-
-# Verify proof
-npm run verify
-
-# Run tests
-npm test
-```
-
-## Circuit Design
-
-### Current Implementation
-
-The initial circuit (`receipt.circom`) implements a simple hash preimage proof:
-
-- **Public Inputs**: Receipt hash
-- **Private Inputs**: Receipt data (job ID, miner ID, result, pricing)
-- **Proof**: Demonstrates knowledge of receipt data without revealing it
-
-### Future Enhancements
-
-1. **Full Receipt Attestation**: Complete validation of receipt structure
-2. **Signature Verification**: ECDSA signature validation
-3. **Arithmetic Validation**: Pricing and reward calculations
-4. **Range Proofs**: Confidential transaction amounts
-
-## Development
-
-### Circuit Structure
-
-```
-receipt.circom          # Main circuit file
-├── ReceiptHashPreimage # Simple hash preimage proof
-├── ReceiptAttestation  # Full receipt validation (WIP)
-└── ECDSAVerify        # Signature verification (WIP)
-```
-
-### Testing
-
-```bash
-# Run all tests
-npm test
-
-# Run specific test
-npx mocha test.js
-```
-
-### Integration
-
-The circuits integrate with:
-
-1. **Coordinator API**: Proof generation service
-2. **Settlement Layer**: On-chain verification contracts
-3. **Pool Hub**: Privacy options for miners
-
-## Security
-
-### Trusted Setup
-
-The Groth16 setup requires a trusted setup ceremony:
-
-1. Multi-party participation (>100 recommended)
-2. Public documentation
-3. Destruction of toxic waste
-
-### Audits
-
-- Circuit formal verification
-- Third-party security review
-- Public disclosure of circuits
-
-## Performance
-
-| Metric | Value |
-|--------|-------|
-| Proof Size | ~200 bytes |
-| Prover Time | 5-15 seconds |
-| Verifier Time | 3ms |
-| Gas Cost | ~200k |
-
-## Troubleshooting
-
-### Common Issues
-
-1. **Circuit compilation fails**: Check circom version and syntax
-2. **Setup fails**: Ensure sufficient disk space and memory
-3. **Proof generation slow**: Consider using faster hardware or PLONK
-
-### Debug Commands
-
-```bash
-# Check circuit constraints
-circom receipt.circom --r1cs --inspect
-
-# View witness
-snarkjs wtns check witness.wtns receipt.wasm input.json
-
-# Debug proof generation
-DEBUG=snarkjs npm run generate-proof
-```
-
-## Resources
-
-- [Circom Documentation](https://docs.circom.io/)
-- [snarkjs Documentation](https://github.com/iden3/snarkjs)
-- [ZK Whitepaper](https://eprint.iacr.org/2016/260)
-
-## Contributing
-
-1. Fork the repository
-2. Create feature branch
-3. Submit pull request with tests
-
-## License
-
-MIT
+For the complete documentation, see the [ZK Circuits documentation](../../docs/apps/crypto/zk-circuits.md).