Fix --xl and --extract options being ignored when using templates

[gh-sandeep]

Summary

Fixes #1296

The --xl (--extract-last) and -x (--extract) command-line options were being completely overwritten when loading a template, instead of being combined with the template's settings. This meant that running:

llm --template my_template --xl

Would ignore the --xl flag if the template didn't have extract_last: true set.

The Bug

In cli.py, when a template is loaded, the code was:

extract = template_obj.extract
extract_last = template_obj.extract_last

This overwrites any CLI flags the user passed.

The Fix

Changed to use or to combine CLI flags with template settings:

extract = extract or template_obj.extract
extract_last = extract_last or template_obj.extract_last

Now the user can use --xl or -x with any template, regardless of whether the template has those options configured.

Testing

• All 470 existing tests pass
• Verified linting (ruff) and formatting (black) pass

Reproduction

Before this fix:

llm "Create an SVG of a pelican riding a bicycle." --save pelican
llm --template pelican --xl
# Returns full markdown response, ignoring --xl

After this fix:

llm --template pelican --xl
# Correctly extracts last fenced code block