fix(cardano): correct getWalletsByTag URL path and encode tag

[jinglescode]

Summary

• getWalletsByTag was calling api/project-wallet/{projectId}/cardano/tag/{tag}, which does not exist on the server. The actual route is api/project-wallet/{projectId}/tag/{tagstring} (see apps/app/src/pages/api/project-wallet/[projectId]/tag/[tagstring].ts). Every call returned a 404 HTML page even when matching wallets existed.
• URL-encode the tag so emails and any tag with @, /, spaces, or other special characters round-trip safely through the path segment.
• Bumped to 0.2.3.

Repro (before patch)

const sdk = new Web3Sdk({ projectId, apiKey, privateKey, network: "mainnet" });
await sdk.wallet.cardano.getWalletsByTag("alice@example.com");
// AxiosError: Request failed with status code 404
// url: api/project-wallet/.../cardano/tag/alice@example.com

After patch

Verified end-to-end against https://utxos.dev with 5 random wallet tags from a real 379-wallet project — every call returned the expected MultiChainWalletInfo[] with matching id and tags.

[1/5] mitsuo.watase@equilibrio-inc.com
  csv  id=1ed8e98b-c909-4126-bf6d-78dbff51420a
  api  id=1ed8e98b-c909-4126-bf6d-78dbff51420a ✓
  tags=["mitsuo.watase@equilibrio-inc.com"] ✓
...
[utxos] sample done. pass=5 fail=0 total=5

Test plan

• Manual: sdk.wallet.cardano.getWalletsByTag(email) returns matching wallets on mainnet
• Manual: tags containing @ work (email tags)
• Add a unit/integration test that asserts the URL path the SDK hits

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