v0.8.2

Skills platform and initial A2A release: define the coherent skills surface after v0.8.1 stabilization. Scope includes plugin-bundled skills, first-party and pluggable skill registries, canonical effective-skill resolution, conservative missing-capability suggestions, and the minimum operator visibility needed for CLI/web/Zerocode to agree on available skills. The WASM plugin program and plugin-management UX move to v0.8.3. Add initial support for opt-in, feature-gated, currently unauthenticated A2A discovery and invocation.