docs(adr): rename ADR-012 — drop Lazar; update title + content + cross-refs

- Rename docs/decisions/adr-012-lazar-conformance.md → adr-012-feature-conventions.md
- Strip "Lazar", "Plan 8/9/10/11", "refactor-logs" refs from all ADRs,
  architecture docs, HTML explainers, and feature/core AGENTS.md files
- Update all incoming links in docs/, packages/*/AGENTS.md, HTML explainers

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/decisions/adr-019-sandcastle-for-agent-orchestration.md

@@ -4,7 +4,7 @@
 **Date:** 2026-05-13
 **Spec:** docs/architecture/agent-first-workflow-and-conformance.md
 **Companion guide:** docs/guides/runbook.md ("Using Sandcastle for agent dispatch")
-**Related:** ADR-011 (TDD foundation), ADR-012 (Lazar conformance), ADR-015 (events and jobs)
+**Related:** ADR-011 (TDD foundation), ADR-012 (feature conventions), ADR-015 (events and jobs)
 
 ## Context