add /_learn command and learning-tour skill (MVP)

[frdzy]

This repo's README.md is a great comprehensive guide, but so full of information that I wasn't sure how to get started.

This PR adds a meta command+skill to take a user on a personalized tour through its concepts, to build familiarity (and optionally mastery).

Summary

• Adds /_learn command as a thin entry point: reads README, sets up _learning-tour branch, invokes skill
• Adds learning-tour skill with survey-first personalization (familiarity vs mastery modes), progress tracking, and live demos
• MVP scope: 3 demo files written (checkpointing, commands+skills, subagents); remaining stops degrade gracefully with a contributor note

Design decisions

• _ prefix convention: /_learn is an infrastructure/meta command, not a workflow command like /weather-orchestrator
• _learning-tour branch isolation: progress file committed to a separate branch so users can git pull main without losing tour state
• Progress file at repo root (not .claude/): avoids permission prompts
• Skill splits into references/: SKILL.md is a ~75-line routing doc; phase logic, progress schema, and doc-surprise examples are in reference files loaded on demand
• Mode detection in the skill, not the command: command stays thin (~40 lines); all conditional logic lives where it can be iterated

File layout

.claude/commands/_learn.md
.claude/skills/learning-tour/
  SKILL.md
  references/phase-details.md
  references/progress-schema.md
  references/doc-surprises.md
  demos/checkpointing.md
  demos/commands-skills.md
  demos/subagents.md

Adding more demo files

Each demo file follows the template in demos/commands-skills.md: repo artifact, steps, expected question, mastery follow-up. Stops without a demo file are handled gracefully — the skill presents the concept from docs + repo artifacts and notes the gap.

Generated with Claude Code

[frdzy]

@shanraisshan hi! I've tested this skill as a clean run a few times and feel this is ready (would recommend a squash commit though to not clobber up the main branch).

I'm open to feedback here too! Also ok to close this out if it doesn't feel like it belongs in the main repo.

I tried out /powerup as well, it's a much faster experience (maybe 5-10min to read through) but doesn't go very deep. However it makes me feel that direction of a skill like this is somewhat validated.

[shanraisshan]

i am working on self awareness as a skill, a skill that will help shape your repo in accordance with best practices. i also like your idea as well, but as you know /powerup is launched today as of 2.1.90, lets wait a bit. also i think there are 100's of public repos with 1000's of skill so i dont want to bloat this repo with skill, commands and agents, that's why this PR is still not closed, rest are.