docs: Document deterministic PRISM DID generation

[yshyn-iohk]

Description

Document the deterministic PRISM DID generation feature per the Deterministic PRISM DID Generation Proposal.

Related: prism-did-method-spec#68 | prism-did-method-spec#69

Requirements

• Document the mnemonic → DID creation flow
• Explain HD derivation path format: m/29'/29'/did-index'/key-usage'/key-index'
• Include test vectors and examples
• Provide code snippets for cloud-agent API, SDK-TS, SDK-KMP, SDK-Swift

Implementation

• New: documentation/develop/deterministic-did-creation.md — guide with derivation path format, algorithm steps, code examples
• Reference existing ADR: documentation/adrs/decisions/2023-05-16-hierarchical-deterministic-key-generation-algorithm.md

Testing

• Build docs site, verify new page renders correctly
• Verify all code examples are accurate