skillscript-runtime v0.26.4

Upgrade impact: none (additive). New tier-3 advisory (info); never blocks compilation.

• New lint append-structured-to-string (tier-3 advisory) — flags $append VAR ${REF} where VAR is a string accumulator and ${REF} is a bare $ op output (a possibly-structured list/object) carrying no .field accessor and no |json filter. Appending a structured value to a string stringifies and fragments it — an array-of-objects comma-splits into a mangled, double-escaped blob. Found dogfooding enter-project ($append DOMAIN_INSTRUCTIONS ${DI} with DI = amp_list_memories's array-of-records; Perry proposal c052581b). The fix is pure authoring, which the message points at: project a scalar field (${REF.detail}) or serialize explicitly (${REF|json}) — both suppress the advisory. It's the $append-side sibling of object-iteration-advisory and reuses the same origin analysis; advisory, not warning, because a $ op's return shape is statically unknowable (a warning would over-fire on legitimate string→string appends). String-target typing reuses append-to-non-list's static-init reasoning.