v0.4.0

What's Changed

• feat(phase1): action execution + HTTP REST API + FCM push notifications by @CrOliX-AltF4 in #15
• feat(ai): butler AI layer — openai/ollama/natsume providers + /api/chat + /api/digest (closes #13, #14) by @CrOliX-AltF4 in #16
• docs(readme): align with LunAtaR pattern — simpler, no API tables by @CrOliX-AltF4 in #17
• chore(release): bump v0.4.0, add CI test gate, ecosystem README by @CrOliX-AltF4 in #18

Full Changelog: v0.3.0...v0.4.0