elevenlabs-say speaks a pipe as it streams

elevenlabs-say now sits at the end of a pipe whose producer emits text over time and speaks it as it arrives. Piped stdin streams by default, no flag needed:

my-llm --prompt "tell me a story" | nix run .#elevenlabs-say

Piped input goes over the ElevenLabs WebSocket input-streaming endpoint. The CLI reads stdin with os.read rather than line iteration, so a token stream that never emits a newline is still spoken instead of buffering until EOF, and a multi-byte character split across two reads is rejoined. Audio chunks pipe into ffplay as they arrive, so playback starts before synthesis finishes.

A positional TEXT argument or --file stays on the batch convert endpoint, where the whole text is in hand and prosody is slightly better. Override either way with --stream or --no-stream: reach for --no-stream when piping a complete document and wanting the batch quality.

It honors --voice, --model, --format, and --output (which writes the file as audio streams in). The default eleven_flash_v2_5 model is the low-latency choice and supports the endpoint; eleven_v3 does not.