docs: add OSS project docs and CI

secrets.env.example

@@ -0,0 +1,25 @@
+# Required for the Telegram bot.
+TELEGRAM_BOT_TOKEN=123456:replace-me
+TELEGRAM_ALLOWED_USER_ID=123456789
+
+# Sync behavior.
+SYNC_INTERVAL=900
+QUERY_DURATION=2
+ENABLE_FDS_SLEEP_DETAILS=true
+
+# Optional local runtime paths for non-Docker runs.
+# Docker Compose already sets these paths.
+# DATA_DIR=/opt/miband-tracker/data
+# DB_PATH=/opt/miband-tracker/data/miband.db
+# STATUS_PATH=/opt/miband-tracker/data/status.json
+# BOT_STATE_DB_PATH=/opt/miband-tracker/data/fitness_bot_state.db
+
+# Optional legacy token bootstrap path.
+# Prefer the Telegram Xiaomi login flow unless you know why you need this.
+# USER_ID=
+# C_USER_ID=
+# SERVICE_TOKEN=
+# SSECURITY=
+# PASS_TOKEN=
+# DEVICE_ID=
+# TARGET_RELATIVE_UID=