Improve developer experience with better error messages and hints

[paulgnz]

Summary

This PR improves the developer experience based on real-world usage feedback from building Proton.Link and related smart contracts.

Addresses feedback from #30

Changes

1. Enhanced Error Parsing (src/utils/detailsError.ts)

• Added helpful hints for common blockchain errors:
  • Insufficient RAM → suggests proton ram:buy command
  • CPU/NET exceeded → explains allocation reset
  • Unknown key → suggests proton key:add
  • Insufficient balance, missing authority, etc.

2. WebAuthn Key Error Message (src/apis/uri/parseUri.ts)

• Before: Generic "Request cancelled from WebAuth.com Wallet"
• After: Clear message explaining WebAuthn keys (PUB_WA_*) cannot sign from CLI, with suggestion to add K1 key

3. Contract Deployment Output (src/commands/contract/set.ts)

• Added progress indicators ("Deploying WASM to account...")
• Better success formatting with checkmarks
• Shows WASM file size
• Handles "contract unchanged" gracefully as a warning instead of error

4. RAM Buy Command (src/commands/ram/buy.ts)

• Fixed class name (was incorrectly named ClaimFaucet)
• Added usage examples to help text
• Improved flag descriptions
• Added proper error handling with parseDetailsError

Before/After Examples

Error Messages

# Before
Error: unknown key

# After
Error: unknown key
Hint: The signing key is not available. Make sure you have added the correct private key: proton key:add

Contract Deployment

# Before
WASM Successfully Deployed:
View TX (link)

# After
Deploying WASM to mycontract...
✓ WASM Successfully Deployed
  Account: mycontract
  Size: 127.45 KB
  TX: abc123...
  View on Explorer (link)

Test Plan

• npm run build passes
• Test proton ram:buy with new error handling
• Test proton contract:set deployment messages
• Test error hints appear for common failures