[reverted] feat: Support custom parameters in extra context

[SilverRainZ]

Summary

ExtraContext.generate() now accepts *args, **kwargs, and load_extra() passes them through from the template. This enables parameterized extra contexts like load_extra('all_docs', count=3).

Changes

• ExtraContext.generate signature: (self, req, *args, **kwargs)
• extra_context_loader forwards *args, **kwargs from the template
• Built-in contexts updated to accept the new signature
• New test root test-extra-context-params with all_docs example
• Docs updated with working examples and literalinclude references
• E2E test and unit test for parameter passing

Usage

@extra_context('all_docs')
class AllDocsExtraContext(ExtraContext):
    def generate(self, req, *args, **kwargs):
        count = args[0] if args else kwargs.get('count', 5)
        return sorted(req.env.all_docs.keys())[:count]

{% set docs = load_extra('all_docs', 3) %}
{% for doc in docs %}
- {{ doc }}
{% endfor %}