Initial commit: telfax - Rust Fax Server

- Modem driver (serialport) with AT command interface
- Class 1 fax protocol (T.30 session, HDLC framing)
- T.4/T.6 image codec (fax crate integration)
- Document conversion (image to fax, TIFF-F output)
- REST API (axum) for fax job management
- SQLite/InMemory job queue
- CLI interface (detect/serve/send/test)
- Integration tests passing

src/modem/mod.rs

@@ -0,0 +1,7 @@
+pub mod driver;
+pub mod at;
+pub mod detect;
+
+pub use driver::ModemDriver;
+pub use at::AtChannel;
+pub use detect::ModemInfo;