fix(expressions): return actual values from and/or operators instead of booleans

[heathdutton]

Fixes #276

The and and or operators were returning boolean values instead of the actual evaluated values. This broke patterns like {% if "x" in (val or "") %} because val or "" evaluated to True instead of the actual string value.

Now matches Python/Django behavior:

• "hello" or "world" returns "hello" (not True)
• "" or "default" returns "default" (not True)
• "hello" and "world" returns "world" (not True)

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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