Customer Support Message Sanitisation

Problem Statement:

A customer support system stores user messages in a database. Before saving, the messages need to be sanitised to remove extra spaces, ensure consistent formatting, and replace prohibited words. Write a program that processes a given message and returns the sanitised version.

Task:

Implement a function that takes a string message and performs the following operations:

• Remove extra spaces (leading, trailing, and multiple spaces between words).
• Ensure the first character of each sentence is capitalised.
• Replace prohibited words with "****".

Input:

• A string message with a maximum length of 1000 characters.
• A list of prohibited words (case insensitive).

Output:

A sanitised string that follows the rules above.

Example:

Constraints:

• Length of the message: 1 ≤ |message| ≤ 1000
• Number of prohibited words: 0 ≤ |prohibited_words| ≤ 100

Notes:

- Sentences in the message end with punctuation marks (e.g., ., !, ?).
- The program should preserve punctuation but adjust spacing and capitalisation accordingly.
- Prohibited words should be replaced completely, regardless of case (e.g., "badword" matches "BadWord").