Add compatibility CLI wallet for hex-ID format

[redlittenyoth]

This PR adds a compatibility CLI wallet that works with the 32-char hex ID format currently used by the miners and basic GUI wallets.

Additionally, I have added a Wallet User Guide in docs/WALLET_GUIDE.md to help new users understand the different wallet formats and how to use the CLI tool. This addresses part of the Documentation Sprint bounty (Issue #72).

Changes:

• Added tools/rustchain_cli_wallet.py
• Added docs/WALLET_GUIDE.md
• Linked guide in docs/README.md

[Scottcjn]

Closing for now: wallet flow uses admin transfer path and is not safe/production-usable for user CLI payout flows.

Please keep participating. To be payout-eligible on resubmission:

1. Map directly to an active bounty issue and claim in that thread
2. Submit focused, non-duplicate changes
3. Include working proof (logs/screenshots/test notes)
4. Keep PR merge-ready (clean diff, no encoding regressions, no placeholder code)

Good active options right now: #99 (challenge), #100 (discovery), #102 (capability), #103 (social), #124 (profile micro-bounty).