Improve a per-module README with inputs / outputs / example

[BOOK318]

Good first issue — documentation.

Pick any … ver 1.0/README.md and add a short section showing:

• What the module takes as input
• What it returns
• A minimal code example

Good candidates: privacy filter ver 1.0, safety checker ver 1.0, intent classifier ver 1.0.

This helps newcomers understand each module without reading the source.