cba9dd4583
file_written artifacts store a JSON envelope ({path, contentHash, size, mode})
whose contentHash points at the real bytes in CAS. The viewer rendered the
envelope itself. StreamQueries now detects the envelope shape (string "path" +
"contentHash") and dereferences the inner hash, falling back to the raw string
when parsing fails or the inner hash is missing (WARN logged — likely evicted).