agentassert-abc 0.5.0 — runtime enforcement plane

0.5.0 adds a runtime enforcement plane — real-time ALLOW/DENY/REDACT/MODIFY decisions on tool calls and model responses — alongside the existing measurement and certification planes. New zero-code-change adoption surfaces ship as optional extras: agentassert-abc[sdk] (wrap() one-liner), agentassert-abc[proxy] (HTTP proxy), agentassert-abc[claude-code] (Claude Code hook). Process invariants (tool allow/block, must-precede, context budget, PII filter, cost ceiling, judge predicate, and more) are authored under invariants.process. Consolidates the former agentassert-typec packages, which continue as thin deprecation shims. See CHANGELOG.md for details.