GUEST: step 1 — lib/guest/conformance.{sx,sh} config-driven driver

Extracted the duplicated conformance plumbing into a single driver:

- lib/guest/conformance.sx — two helper fns that emit (gc-result NAME P F T)
  lines for the bash side to grep: gc-dict-result for runners returning
  a {:passed :failed :total} dict, and gc-counters-result for guests that
  bump a global pass/fail counter from a test file load.

- lib/guest/conformance.sh — config-driven bash driver. Sources a per-lang
  conf, locates sx_server, runs sx_server in either single-session "dict"
  mode (one preload + many suite evals) or per-suite "counters" mode
  (fresh sx_server per suite, with shared preloads). Aggregates and writes
  scoreboard.{json,md} via per-lang emit_scoreboard_* functions.

- Ported lib/prolog/conformance.sh and lib/haskell/conformance.sh down to
  one-line wrappers that exec the shared driver against their .conf file.

Verification:
- Prolog: 590/590 — diff vs baseline is timestamp-only.
- Haskell: 156/156 — significantly higher than the 0/18 in baseline. The
  old conformance.sh was buggy (its `(ok-len 3 ...)` grep never matched,
  defaulting every program to 0 pass / 1 fail). Updated baseline to the
  true count; no actual test regressed. Plan baseline cell updated.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

lib/guest/conformance.sx

@@ -0,0 +1,40 @@
+;; lib/guest/conformance.sx — shared helpers for the guest conformance driver.
+;;
+;; The bash driver lib/guest/conformance.sh loads this file and then for each
+;; suite emits an (eval "...") form whose result is a tagged list:
+;;
+;;     (gc-result NAME PASSED FAILED TOTAL)
+;;
+;; The driver greps these from sx_server's output and aggregates them.
+;;
+;; Two suite shapes are supported:
+;;
+;;   :dict     — runner expression returns a dict with :passed/:failed/:total.
+;;               (gc-dict-result "parse" (pl-parse-tests-run!))
+;;
+;;   :counters — runner has no return value, mutates pass/fail global counters.
+;;               (gc-counters-result NAME P0 F0 PASS FAIL)
+;;               where P0/F0 are the counters captured BEFORE the suite ran
+;;               and PASS/FAIL are the counters AFTER.
+
+(define
+  gc-dict-result
+  (fn
+    (name r)
+    (list
+      (quote gc-result)
+      name
+      (get r :passed)
+      (get r :failed)
+      (get r :total))))
+
+(define
+  gc-counters-result
+  (fn
+    (name p0 f0 p1 f1)
+    (list
+      (quote gc-result)
+      name
+      (- p1 p0)
+      (- f1 f0)
+      (- (+ p1 f1) (+ p0 f0)))))