v1.1.5

fix: file write/append/move create parent dirs (mkdir -p)

Live QA surfaced it: writing or moving a file under a path whose parent
doesn't exist yet failed with a bare ENOENT the agent then had to diagnose.
`write`, `append`, and `move` now create missing parent directories first, so
writing a new file under a fresh path just works. Adds a directory-redirect
test for `read` while here.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>