importAttachments lands files into a card's attachments/ (created on
first import — the one folder the app ever makes there), never
overwriting and never refusing a name: collisions auto-rename
Finder-style, counting up from 2, with a same-named subfolder
blocking a name exactly like a file. Sources are validated before any
copy; a failed copy removes the partial destination and throws naming
the source file; a multi-file batch stops at the first failure with
earlier files staying landed. listAttachments is the flat surface:
top-level regular files only, Finder-sorted, subfolders and hidden
entries excluded and untouched; a missing attachments/ lists empty.
11 new unit tests; 245 total green.
Claude-Session: https://claude.ai/code/session_018BjQRYBR6jQja3jCRi5S3A
rzen
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