v0.4.12

Core validator

• CDATA-aware leaf payload checks: the parser now preserves adjacent text and CDATA segments, retains entity references in plain text, and enables accurate warnings for URL, Extension, and CreativeExtension payloads that should be wrapped in CDATA.
• New advisory rules: added VAST-2.0-url-cdata, VAST-2.0-extension-cdata, and VAST-2.0-creative-extension-cdata as warning-level guidance for fragile leaf-text payloads.

Docs

• Rules catalog fixed: RULES.md now matches the shipped 121-rule catalog, including SIMID entries, the quartile-tracking warning, and correct warning severity for the HTTP transport rules.
• Count drift removed: refreshed stale 118 rules references across the main README, package metadata, MCP docs, roadmap, and architecture docs.
• VS Code README resynced: restored the embedded rule list with vastlint.org links and added parity coverage so the extension README stays aligned with the canonical rule catalog.

Tests

• Rules markdown parity: added crates/vastlint-core/tests/rules_markdown.rs so RULES.md count, IDs, and severities must stay aligned with all_rules().