Fix: make image analysis work with any topic containing image data (#144)

* Bugfix: make image analysis work with any topic containing image data

- Remove "Image" in topic name requirement
- Add content-based image detection using "data" field
- Update tool descriptions for clarity

* Add optional expects_image parameter with robust image detection
Includes is_image_like() helper that checks image-specific fields to
distinguish images from pointclouds etc.

* Track image parsing state and exclude data field

* Add was_parsed_as_image tracking to accurately report whether image
parsing occurred. Filter out large 'data' field from image responses
since image is already saved to disk for analysis.

* Create a centralized parse_input() function in websocket_manager.py
that encapsulates all parsing logic with expects_image hint handling.

* Refactor the request method in WebSocketManager to use parse_input. This will also allow service responses to handle image data if a service returns image data:

* Removed Union/Optional and using a string instead. Union/Optional are highly bugged in fastmcp.

* Added recognition for jpeg/compressed formats + restructure image analysis process.

* Added launch file for realsense example + cleaned up the README.md

Author: stex2005