Sub-Issue 2: Summon Wallet Capability Builder

[Andre-Diamond]

Problem: buildMultisigWallet returns undefined for Summon, and buildWallet uses a placeholder native script without feature detection.

Tasks:

• Create a Summon-specific builder that:
  • Decodes payment_script and optional stake_script CBOR
  • Computes the payment address from the decoded payment script
  • Computes stake address or stake credential hash when applicable
  • Returns a normalized capability object (payment/stake, script types, required signers)
• Decide how to surface this object (new helper or extend buildWallet return shape).

Affected files:

• src/utils/common.ts
• src/types/wallet.ts
• New shared utility (if introduced by Sub-Issue 1)

Acceptance:

• Summon wallets have a reliable address, script metadata, and feature flags without relying on MultisigWallet.