Docs + CI for the Chez-only substrate

Rewrite the README, CLAUDE.md build/architecture sections, test/chez/README,
and conformance SPEC for the Janet-free world: bin/joltc + make test, the
self-hosting bootstrap, the frozen JVM-sourced corpus. CI installs Chez + JDK/
Clojure and runs 'make test' (was Janet/jpm).

jolt-cf1q.6

test/chez/README.md

@@ -1,60 +1,41 @@
 # Chez test harness
 
-The correctness gate for jolt on Chez (epic jolt-cf1q). Correctness is judged
-against the JVM-sourced conformance spec — no Janet decides pass/fail. The spec
-itself lives in `test/conformance/` (see its `SPEC.md`); this directory holds the
-Chez runners and unit tests.
+The correctness gate for jolt. Pure Chez (+ Clojure for the JVM oracle), no Janet.
+Correctness is judged against the JVM-sourced conformance spec; the spec itself
+lives in `test/conformance/` (see its `SPEC.md`). Run the whole gate with `make
+test` from the repo root.
 
 ## The spec corpus
 
-- `corpus.edn` — the contract: ~2920 rows `{:suite :label :expected :actual}`,
-  with `:expected` sourced from reference JVM Clojure. Valid as both EDN and Janet
-  data. Generated by `test/conformance/regen-corpus.clj` (the answers) over the
-  case list from `extract-corpus.janet` (the `:actual` strings, pulled from
-  `test/spec/*.janet` and `conformance-test.janet`).
-- `extract-corpus.janet` — re-derives the case list when spec rows change. Writes
-  only when `JOLT_EXTRACT_CORPUS_OUT` is set, so a gate run never clobbers the
-  JVM-sourced `corpus.edn`. After re-deriving, re-source the answers with
-  `regen-corpus.clj`.
+`corpus.edn` is the contract: ~2920 rows `{:suite :label :expected :actual}`, with
+`:expected` sourced from reference JVM Clojure by `test/conformance/regen-corpus.clj`.
+It is frozen (the canonical source) — add or change cases here, then re-source the
+answers with `regen-corpus.clj` and re-certify with `test/conformance/certify.clj`.
 
-## The standing gate
+## The gate runners (`host/chez/`)
 
-`run-corpus-zero-janet.janet` runs every corpus case through the zero-Janet
-spine: read → analyze → IR → emit → eval, all on Chez (the analyzer is
-`jolt.analyzer` cross-compiled to Scheme over `host-contract.ss`). Each result is
-compared by value-equality against the JVM `:expected`. A `known-fail` allowlist
-covers cases jolt can't match because Chez has no JVM host (Java classes, arrays,
-`BigDecimal`, opaque host-object printers, …); the gate fails only on a NEW
-divergence or if the pass count drops below the floor.
+- `run-corpus.ss` — runs every corpus case through the spine (read → analyze → IR →
+  emit → eval, all on Chez), comparing each result by value-equality against the JVM
+  `:expected`. A `known-fail` allowlist covers cases jolt can't match because Chez has
+  no JVM host (Java classes, arrays, `BigDecimal`, opaque host-object printers, …);
+  the gate fails only on a NEW divergence or if the pass count drops below the floor.
 
-    JOLT_CHEZ_ZEROJANET_CORPUS=1 janet test/chez/run-corpus-zero-janet.janet
-    JOLT_CORPUS_LIMIT=200 …            # every-Nth stride, fast iteration
+      chez --script host/chez/run-corpus.ss
+      JOLT_CORPUS_LIMIT=200 …            # every-Nth stride, fast iteration
+      JOLT_CHEZ_ZJ_FLOOR=N …            # override the floor (default 2678)
 
-Floor: 2678 (`JOLT_CHEZ_ZJ_FLOOR` overrides). Raise it as host gaps close.
+- `run-unit.ss` — host-specific unit cases (`test/chez/unit.edn`) that aren't in the
+  JVM-portable corpus: dot-forms, java statics, io, reader, walk, vars/namespaces,
+  refs. Each `:expr` is evaluated in-process and its printed value compared to a baked
+  `:expected` (`:throws` asserts a raise).
 
-## Unit tests
+- `selfcheck.sh` — self-host fixpoint: `bootstrap.ss` rebuild byte-equals the
+  checked-in seed (`host/chez/seed/`).
+- `smoke.sh` — real `bin/joltc -e` CLI smoke.
 
-`_*.janet` drive `bin/joltc` (the pure-Chez CLI; `JOLT_BIN` overrides) one
-subprocess per case and compare the last stdout line against a baked expected
-value. `:throws` asserts a non-zero exit. Each file targets one area —
-`_type`/`_class`/`_seqpred` (taxonomy + predicates), `_str`/`_strns`/`_reader`
-(strings + reader), `_io`/`_ioreader`/`_insttime`/`_javastatic` (host interop),
-`_dynbind`/`_var_meta`/`_ns` (vars + namespaces), `_atomwatch`/`_walk`/`_dotform`
-/`_stdlib` (refs, walk, dot-forms, stdlib). Run one with
-`janet test/chez/_type.janet`.
+## Other Chez tests
 
-## Self-host gates
+- `values-test.ss` — the value model (nil/truthiness/collections). `make values`.
+- `bench-chez.ss` — compute bench through the pipeline (opt-in; not in the gate).
 
-- `spine-test.janet` — the zero-Janet compile/eval spine end to end.
-- `cli-test.janet` — `bin/joltc -e` behavior.
-- `bootstrap-test.janet` — `host/chez/bootstrap.ss` rebuilds the prelude + image
-  from source on Chez and matches the checked-in seed (`host/chez/seed/`).
-- `fixpoint-test.janet` — the on-Chez compiler reproduces itself (stage2 == stage3,
-  prelude pstage3 == pstage4).
-
-## Bench
-
-`bench-pipeline.janet` (opt-in via `JOLT_CHEZ_BENCH=1`) times fib + mandelbrot
-through the real pipeline against the spike ceiling. Skipped in the gate.
-
-All Chez runners skip cleanly when `chez` is not on PATH.
+All runners assume `chez` on PATH.