feat: add getProjectWalletsByTag and normalize wallet shape

[jinglescode]

Summary

• Adds sdk.wallet.getProjectWalletsByTag(tag) to WalletDeveloperControlled, consuming the existing GET /api/project-wallet/:projectId/tag/:tag backend endpoint.
• Fixes a latent shape-cast bug in getProjectWallet and getProjectWalletsByTag: the backend returns a flat Web3ProjectWallet (pubKeyHash, stakeCredentialHash at top level) but the SDK was casting it as the nested MultiChainWalletInfo (chains.cardano.*). Any caller reading wallet.chains.cardano.pubKeyHash previously got undefined. A normalizeWalletInfo helper now maps flat → nested at the SDK boundary. Spark is intentionally omitted because the backend doesn't persist Spark public keys.
• Removes a dead walletInfo.chains.spark gate in getWallet. Spark wallets derive entirely from the mnemonic; the gate prevented the spark branch from ever running in production.
• Bumps version 0.2.0 → 0.2.1.

API

const wallets = await sdk.wallet.getProjectWalletsByTag("treasury");
console.log(`Found ${wallets.length} treasury wallets`);

• URL-encodes the tag (team/alpha beta → team%2Falpha%20beta)
• Throws on empty/whitespace tag
• Returns MultiChainWalletInfo[] with chains.cardano populated

Out of scope (deferred)

• getProjectWallets (paginated list) has a separate envelope-shape bug — SDK expects {data, pagination} but the backend returns a flat array. Not touched here.
• POST /api/project-wallet silently drops chains.spark — would require a Prisma schema migration.

Test plan

• pnpm jest src/sdk/wallet-developer-controlled/index.test.ts — 40/40 passing
• Type-check passes for changed files (pre-existing errors elsewhere)
• QA review (code review + cross-check against backend handlers and Prisma schema) — verdict PASS-WITH-CONCERNS, zero blockers
• Smoke test against staging API (reviewer)

🤖 Generated with Claude Code