markdown.lua now mirrors the launcher byte-for-byte: M.render takes an
optional t 6th arg that the launcher threads its ctx.t through for the
image-missing placeholder. Pure-additive parameter — existing test
callers (which never invoke M.render) are unaffected.
manifest.lib: bump 0.2.0 -> 0.3.0. The render-signature change is
API-shaped; downstream consumers that call the helper directly may want
to opt in to the new arg.
Per ADR-0037 Tests-as-Libs Convention. Renamed on Gitea +
moved locally to lib-sporel/launcher-test. fsm.lua and dofile
pattern preserved; Pre-S15 drift-check still applies.
