Add confidential RFQ development flow and refresh demo tooling

[gstohl]

The existing RFQ settlement exposes funded trade terms publicly. Add a confidential RFQ development flow using a joint shielded escrow: both parties approve the same encrypted settlement, and either party can independently recover its own funds after expiry.

Includes the Cairo contract, Node SDK with strict action/proof validation and durable recovery metadata, a loopback development workspace, and updated product/agent documentation. Confidential mainnet activation remains disabled; local execution uses simulated proof facts, with real proofs, independent wallet integration, and review still required.

Refresh the demo tooling with the selected ElevenLabs narration, smoother macOS-style cursor movement, shorter framed scenes, natural Chat samples, and automated voice-tail verification. Ignore the whole artifacts/ directory and remove previously tracked artifacts while preserving local files. Keep the existing mainnet submission transactions and durable deployment evidence.

Validation:

• Production build, typechecks, full regression suite, and production CSP checks passed.
• 134 Cairo tests, contract class-pin verification, SDK integration, and 26 adversarial cases passed; the latter also exercised the pinned mainnet pool class on local devnet with simulated proof facts.
• Browser settlement, independent refund, and cross-origin request rejection passed.
• Packaged SDK import and final 136-second demo validation passed, including all 12 voice endings.

No new mainnet transactions were submitted, and the video remains a local artifact pending publication.