v0.1.3

send: attach any file (--file), one message per file

Files go through Messenger's own file input (images are still pasted so
they arrive as photos), streamed in 3MB base64 chunks, max 25MB each.
Every file and the text is submitted and confirmed as its own new
outgoing message below the newest one seen before sending, so another
message (or re-mounted history) can no longer confirm a send that did
not happen. Enter is retried while the attachment still sits in the
composer. `unsend` skips the empty rows left by earlier unsends.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>