Performance:
- Beware list-ref in a loop (O(n²) trap)
- Consolidated performance section with data structure selection rationale
- for/fold for single-pass result building
Parameters and dynamic scope:
- Good uses: ports, logging, config, test fixtures
- Bad uses: hidden global state, implicit argument passing
- Document when functions read from parameters
Also simplified Continuations section (parameterize now has its own section).
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