07048983e0
Introduce a `ts type-equiv` Markdown fence: a verbatim paste of a source type definition that `scripts/verify-type-equiv.ts` drift-checks against the source symbol via the TypeScript parser, with provenance in a central `scripts/type-equiv.manifest.json` kept 1:1 with the blocks. doc-typecheck recognizes the same fence, skips compiling it (not standalone-compilable), and excludes it from the opt-out ratio. Wired into the `doc-sync` chain.