Add READMEs for the repo and every generation, root CLAUDE.md and .gitattributes

The root README has the timeline of all generations since 2009. Each generation folder explains its hardware and what is in it. .gitattributes turns off line-ending conversion so all files stay as they were.

2019-teensy-nrf24/README.md

@@ -0,0 +1,16 @@
+# 2019–2022: Teensy robot and Teensy remote
+
+The SSC-32 was replaced by a Teensy 3.6 on the robot that drives the 18 servos itself, and a second Teensy
+became the handheld remote. They talk over nRF24L01 (RF24Network, channel 90). The robot has no IK of its own:
+it plays the servo angles it receives, which come from the Unity simulation (`../2018-unity-sim/`) through the
+remote's USB passthrough, or from the remote's sliders.
+
+| Folder | What |
+|---|---|
+| `Hexapod_Teensy/` | robot: PWMServo on 18 pins, per-servo ranges and trims (`config.h`), MPU6050, nRF24 (CE 39, CSN 15, SCK 14) |
+| `remote/` | remote: Nextion screen, 6 joystick axes with EEPROM calibration, MPU6050, nRF24 (CE 9, CSN 10), USB passthrough at 250000 |
+| `remote-nextion/` | `remote.HMI`, the Nextion Editor design (6 pages: servo monitor, upload screen) |
+| `remote-case/` | 3D-print files of the remote case and bezel, an Arduino Mega cover plate, a font |
+| `tests/` | May 2019 bring-up sketches: SSC-32 command emulator (first step to replacing the SSC-32), nRF24 and MPU6050 tests with the robot's pins |
+
+Its hardware facts (pins, ranges, trims) were carried over into `../2026-current/robot/Config.h`.