shep: allar útgáfur og eldri útgáfur

Added
- Shep whisper types into a pty sheep, and the operator docs say how
- Common flags take a one-letter short form
- Shep attach shows a pty sheep's live terminal and sends keys in
- A sheep config takes a pty key that Windows refuses by name
- A pty sheep survives a shepherd reload

Fixed
- A GET decodes a chunked body, so the dog index loads
- Cut the whisper and stdin pump doc comments to their IR-47 limits
- Attach keeps reading the sheep's output while a keystroke is in flight
- Attach detaches during a stalled write, restores on SIGTERM and refuses Windows before dialling
- Attach flushes typed text when stdin closes and turns off the modes a sheep switched on
- The local attach arm runs on unlocked stdout and stderr
- Request::PtyInput carries bytes, not text
- Attach sends a read bigger than one frame as several requests
- BusEvent::PtyOut carries bytes, not text
- A pty sheep's output reaches attach as bytes