v0.5.0

What's Changed

• fix: enforce AgentKit result and lifecycle invariants by @ebarti in #41
• fix: verify required vendor SDK options by @ebarti in #42
• feat: enforce strict structured output primitives by @ebarti in #43
• fix: validate structured output across providers by @ebarti in #44
• feat: enforce runtime domain invariants by @ebarti in #45
• feat: add task compatibility preflight by @ebarti in #46
• feat: add bounded runtime readiness probes by @ebarti in #47
• fix: delegate default model selection to providers by @ebarti in #48
• feat: add task deadlines and cancellation by @ebarti in #49
• release: prepare v0.5.0 by @ebarti in #50

Full Changelog: v0.4.0...v0.5.0