serialize_value: lists with symbol head emit (fn args...) not (list fn args).
This lets the client SX parser recognise special forms like let, when, cond
inside component-defs. Data lists (starting with non-symbols) keep the
(list ...) wrapper.
Fixes "Undefined symbol: let" WASM error that broke all island hydration.
Header island now reaches the JIT evaluator (fails on for-each VM error,
not parsing). Geography, SXTP, CEK pages fully rendered.
Removed debug logging (ssr-debug, debug dump, debug endpoint).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>