Threading macros (recursive; the expand-once cache makes that free) and declare
(a no-op on Jolt — forward refs resolve via pending cells). They live in 00-syntax
because the analyzer itself uses -> and declare; validated by conformance 228x3
(the bootstrap-compiled analyzer expands them).
conformance 228/228 x3, clojure-test-suite 3930.
The hot control macros now live in the Clojure syntax tier. This was blocked
before: as interpreted overlay macros they re-expanded on every eval, timing out
a battery file (3930->3911). With the expand-once macro cache (prior commit) they
expand a single time with zero runtime cost, so moving them is free.
conformance 228/228 x3, clojure-test-suite 3930 (9 timeouts, not 10), full suite
green, bench flat (overlay vs janet macros within noise).
New 00-syntax tier loaded FIRST (before 00-kernel), interpreted defmacros, so the
control macros the compiler and every later tier depend on can live in Clojure.
Validated by moving when: the kernel tier, self-hosted analyzer and seq/coll
tiers all compile against the overlay when. Constraint: syntax-tier macros may use
only special forms + core-renames seed primitives (not second/peek/kernel fns).
conformance 228/228 x3, full suite green.
