Function assemble_context 

pub fn assemble_context(paths: Vec<String>, base_dir: &Path) -> Result<String>

Assembles context from multiple files into a single markdown document.

Arguments

• paths - File paths to include
• base_dir - The base directory to resolve relative paths against

Returns

• Ok(String) - Markdown containing all readable files (empty if none succeed)
• Err - If base_dir cannot be canonicalized

Behavior

• Validates each resolved path stays within base_dir (prevents directory traversal)
• Skips files that escape the project directory, can’t be read, or are binary/too large
• Continues even if some files fail