Capture a def's reader metadata on the Chez var. The :def emit now lowers a def
with non-empty metadata to def-var-with-meta!, which stores the user meta
(^:private / ^Type tag / docstring -> {:doc}) in an eq side-table keyed by the
var-cell. jolt-meta of a var-cell merges that onto {:ns :name} derived from the
cell, so every var reports {:ns :name} like Clojure with the def-time meta
layered on. (^{:map} metadata on a def name stays uncompilable for the compiler
generally — analyzer rejects it, the Janet back end punts to its interpreter,
which Chez lacks — so it's out of subset, not a meta-capture gap.)
Added natives-meta.ss to the prelude-cache fingerprint. Prelude parity
1969 -> 1972, 0 new divergences; the three var-metadata allowlist entries
(^:private / ^Type tag / docstring) dropped. New focused gate
test/chez/_var_meta.janet.
meta/with-meta resolved to jolt-nil. Chez values don't carry metadata, so
collections use an identity-keyed side-table: with-meta returns a fresh copy of
the value (new identity) and records its meta there, leaving the original
unchanged (immutable-with-meta) and dropping meta on a later copying op. Symbols
carry meta in their existing field; meta on a non-metadatable value is nil.
vary-meta works over these. with-meta on a fn stays fn? (jolt is lenient).
emit.janet carries a quoted symbol's reader metadata (^:foo bar) onto the
emitted jolt-symbol so (meta 'x) sees it; symbol = still ignores meta.
Prelude parity 1701 -> 1723, 0 new divergences. jolt-rkbc.
