fix: add BRIDGE_CODE env var fallback for bridge session code

Some Android/Termux shells may not pass command-line arguments
correctly to dynamically-linked PIE binaries. Add BRIDGE_CODE
environment variable as a fallback so the code is passed via
both os.Args and the env.

Author: bgwastu

bridge/main.go

@@ -74,10 +74,10 @@ func main() {
 	if wsURL == "" {
 		fatal(`Missing env var: BRIDGE_WS_URL`)
 	}
-	if len(os.Args) < 2 {
-		fatal("Usage: cya-bridge <session code>")
-	}
 	code := os.Args[1]
+	if !sessionCodePattern.MatchString(code) {
+		code = os.Getenv("BRIDGE_CODE")
+	}
 	if !sessionCodePattern.MatchString(code) {
 		fatal("Usage: cya-bridge <session code>")
 	}

server/static/connect-unix.sh

@@ -61,4 +61,4 @@ else
   exit 1
 fi
 chmod +x "${TMPDIR}/${BIN_NAME}"
-BRIDGE_WS_URL="${BASE_URL/http/ws}/ws" "${TMPDIR}/${BIN_NAME}" "${CODE}"
+BRIDGE_WS_URL="${BASE_URL/http/ws}/ws" BRIDGE_CODE="${CODE}" "${TMPDIR}/${BIN_NAME}" "${CODE}"