docs: rewrite README, sync CLAUDE-BASE template, and update init command

- README: comprehensive rewrite with table of contents, structured sections
  for GitHub workflow, skills/agents, CLI installer, and installation guides
- CLAUDE-BASE: sync with learning-journey CLAUDE.md — replace verbose ASCII
  diagrams with concise table format, add autonomous PR review with auto-merge,
  unaddressed work tracking via GitHub issues, actionable issue requirements,
  and streamlined slash commands section
- init command: expand permissions setup from gh-only to full agent workflow
  (git, node, npm, npx, shell utilities) for autonomous sub-agent operation

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: futuregerald