fix(ralph-wiggum): isolate ralph-loop state per session

[RooseveltAdvisors]

Summary

• Fixes cross-session interference when running ralph-loop in one Claude Code session while another session is open in the same project
• The stop hook was using a shared state file (.claude/ralph-loop.local.md) that caused unrelated sessions to get hijacked into the loop when they tried to exit

Changes

• New SessionStart hook (session-start-hook.sh): Captures session_id from hook input and exports it as CLAUDE_SESSION_ID via CLAUDE_ENV_FILE, making it available to bash commands
• Session-specific state files: Setup script now creates .claude/ralph-loop.{SESSION_ID}.local.md instead of the shared filename
• Stop hook session awareness: Extracts session_id from its JSON input and only looks for the matching state file — other sessions' loops are invisible
• Updated cancel-ralph: Handles both session-specific and legacy state filenames

How it works

Before	After
Session A starts loop → creates shared .claude/ralph-loop.local.md	Session A starts loop → creates .claude/ralph-loop.abc123.local.md
Session B finishes task → stop hook sees shared file → hijacked	Session B finishes task → stop hook looks for .claude/ralph-loop.xyz789.local.md → not found → exits normally

Test plan

• Start a ralph-loop in Session A (/ralph-loop "test task" --max-iterations 5)
• Open Session B in the same project, do some work, verify it exits cleanly without entering the loop
• Verify Session A's loop continues to iterate correctly
• Verify /cancel-ralph works in the session that started the loop
• Verify fallback random ID when CLAUDE_SESSION_ID is unavailable (new session before restart)

🤖 Generated with Claude Code