feat: Hacash L2 Channel Interactive Guide

[enioxt]

Problem

From Telegram community analysis:

• "I opened a channel with 0.5 HAC but nothing changed"
• "There are so many technical details in Hacash and someone needs to teach us"
• "I also opened L2 but closed it because I didn't know how to use it"

hacash.org has L2 docs but they're theoretical, not practical step-by-step.

Proposal

Interactive L2 tutorial at egos.ia.br/learn/hacash-l2

Features

• Visual explainer: what is a channel, why use it, when to use it
• Step-by-step guide with screenshots: open → deposit → transact → close
• Live channel stats from network (open channels, total deposited)
• FAQ addressing exact community confusions
• Links to desktop wallet download + setup
• Common mistakes and how to avoid them

References (not duplicating)

• hacash.org/layer-2-intro — theoretical overview
• hacash.org/layer-2-wallet — wallet link
• We add: PRACTICAL hands-on guide with real screenshots

PRD: docs/plans/HACASH_COMMUNITY_TOOLS_PRD.md — Project 3