docs(readme): reflect v0.0.1 CLI-agent + bwrap reality

The previous README described the v0.0.2 Podman/Python runtime that
was explicitly deferred in the DESIGN.md pivot. Bring it in line:

- Milestone scope: v0.0.1 is bwrap + CLI tools (Claude Code, Gemini,
  Codex); Podman/Python/litellm deferred to v0.0.2. No Python on
  host, period.
- Sandboxing section now describes actual bwrap baseline flags
  (--unshare-user-try, --unshare-net, --cap-drop ALL) and the
  two-network-policy design (none | api-only | open).
- Prerequisites: bubblewrap, inotify-tools, AppArmor profile for
  Ubuntu 24.04, at least one CLI tool authenticated.
- CLI reference split into "wired today" (init, doctor, help) and
  "planned for later phases" — no more overpromising.
- Project Status names each phase and its state (01-03 done,
  04 in progress, 05 planned).
- License corrected: MIT -> Apache-2.0 (matches the LICENSE we
  just committed).
- Links SECURITY.md and CONTRIBUTING.md.

When README and DESIGN.md disagree, DESIGN.md wins (stated explicitly).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: foobarto