v2.6.2

runcode v2.6.2 (2026/08/12)

writeChunk now checks \ifruncode before doing any staleness verification:
in cache mode (e.g. Overleaf via make_overleaf.py-style workflows) it
trusts an existing cached file outright with zero subprocess calls,
matching runExtCode/inln's existing cache-mode behavior. The v2.6.1 MD5
checksum check ran unconditionally, including in cache mode, where it
defeated the point.

Adds examples/WriteChunkCacheTest/ as a permanent regression test
covering the full factorial design (ifruncode true/false x generated-file
missing/fresh/stale).