Onboard me to this project at $CLAUDE_PROJECT_DIR.

1. Create required directories if they don't exist:
   mkdir -p thoughts/shared/handoffs/<project-name> .claude

2. Explore the codebase using available tools:
   - Try: tldr tree . && tldr structure .
   - Fallback: find . -type f -name "*.py" -o -name "*.ts" -o -name "*.js" | head -50

3. Detect tech stack (look for package.json, requirements.txt, Cargo.toml, go.mod, etc.)

4. Ask the user about their goals using AskUserQuestion

5. Create a YAML handoff at thoughts/shared/handoffs/<project-name>/onboard-<date>.yaml:
   ---
   date: <ISO date>
   type: onboard
   status: active
   ---
   goal: <user's stated goal>
   now: Start working on <first priority>
   tech_stack: [list of detected technologies]
   key_files:
     - path: <important file>
       purpose: <what it does>
   architecture: <brief description>
   next:
     - <suggested first action>