feat: add project create command with E2E integration tests

[ckrough]

Summary

• Add agentspaces project create command for initializing new projects with templates
• Add comprehensive E2E integration tests (23 tests) with proper isolation
• Remove deprecated docs scaffold command
• Update documentation with task description standards for Beads

Changes

New Features

• Project initialization command: agentspaces project create [-n name] [-d description] [--python]
  • Creates skeleton: CLAUDE.md, README.md, docs/, .claude/
  • Optional Python language pack: pyproject.toml, ruff, mypy, pytest, pre-commit, GitHub Actions
  • Runs git init if needed, shows preview with confirmation

Testing

• 23 new integration tests in tests/integration/cli/test_project_create.py
• Test categories: basic creation, Python naming, error handling, content validation, git integration, edge cases
• pytest integration marker for selective runs: pytest -m integration or pytest -m "not integration"
• Isolated fixtures: temp directories, git config isolation

Removed

• docs scaffold command (replaced by project create)
• TODO.md template (Beads replaces task tracking)
• deployment.md template (not needed for MVP)

Documentation

• Added task description standards to CLAUDE.md for Beads issues
• Updated README with project initialization examples

Test plan

• All 286 tests pass (263 unit + 23 integration)
• Integration tests properly isolated (run twice with same results)
• Marker filtering works correctly
• ruff and mypy pass
• Manual CLI test confirms command works end-to-end