Initial implementation of Sahsa Clock

Pygame framebuffer clock for Le Potato (ARM Debian) with aiohttp webhook server.
Renders 12-hour clock directly to /dev/fb0 (no X11/Wayland). Supports full-screen
message overlays pushed via a browser dashboard or Bearer-token API. Includes
first-run setup wizard, session-based dashboard auth, bcrypt password storage,
per-IP rate limiting, and systemd service unit.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

sahsa-clock.service

@@ -0,0 +1,27 @@
+[Unit]
+Description=Sahsa Clock Display
+After=network.target
+DefaultDependencies=no
+
+[Service]
+Type=simple
+User=pi
+WorkingDirectory=/opt/sahsa_clock
+
+# Tell SDL to render directly to the Linux framebuffer (no display server needed)
+Environment=SDL_VIDEODRIVER=fbcon
+Environment=SDL_FBDEV=/dev/fb0
+
+# Disable console blanking so the TV stays on
+ExecStartPre=/bin/sh -c 'echo -ne "\033[9;0]" > /dev/tty1'
+
+# If using a virtualenv (recommended):
+ExecStart=/opt/sahsa_clock/venv/bin/python3 /opt/sahsa_clock/main.py
+# If using system Python instead, replace the line above with:
+# ExecStart=/usr/bin/python3 /opt/sahsa_clock/main.py
+
+Restart=always
+RestartSec=5
+
+[Install]
+WantedBy=multi-user.target