Declare weaver-spec v0.1.0 compatibility + run conformance in CI

[dgenio]

Why

ChainWeaver has the kernel-backed executor issue (#89) and "Flow as Capability" doc (#90), but no formal declaration of spec compatibility and no CI gate to prevent future drift. This is the equivalent of agent-kernel#58.

Without this, the weaver-spec compatibility matrix cannot be filled in for ChainWeaver, and there's no automated check that ChainWeaver continues to honor Invariant I-07 (delegates execution to the kernel).

Acceptance Criteria

• README section: "Weaver Spec Compatibility: v0.1.0" stating which invariants ChainWeaver satisfies (at minimum I-07)
• CI job that runs the weaver-spec conformance suite (once dgenio/weaver-spec#4 ships)
  • Can be a placeholder/stub step initially, activated when the conformance suite is published
• Update weaver-spec compatibility matrix with ChainWeaver's tested version
• Verify that any CapabilityToken requests and Frame consumption align with the JSON Schemas in contracts/json/

Dependencies

• Conformance suite: dgenio/weaver-spec#4
• Kernel-backed executor: dgenio/ChainWeaver#89 (should land first so there's something to validate)

Context

Part of Milestone E0 — Connect + Align Boundaries.