bench: re-ratify compile_check baseline (closes #45)

Re-baseline bench/baseline_compile.json, last ratified 2026-05-15
(20add51, mut.4-tidy). check_ms shifted +35..47% uniformly across all
12 fixtures (~1.8-3.3ms -> ~2.4-4.7ms); build_O0_ms rose ~10%
(90->100ms) but stayed inside its 20% tolerance and so never tripped.

RATIFY, not a regression. The decisive signal is that the check_ms
drift is *uniform* across every fixture regardless of complexity
(hello +35%, nested_pat +35%). Fixture-independent drift means the
cost lives in shared per-invocation work, not in any fixture-specific
checker path. Two concrete shared-cost growths fully account for it:

  - examples/prelude.ail grew 116 -> 153 lines (+32%); every
    `ail check` parses and typechecks the full prelude.
  - the kernel_stub module is now injected alongside prelude on every
    check (landed in raw-buf prep.3, 9339279, #33) — a whole extra
    module parsed + typechecked per invocation.

Both are real modules added by wanted features, not a quadratic
blow-up. There is no fixable type-checker regression hiding here; the
+0.8ms is the parse+typecheck cost of more shared source. The throughput
baseline (bench/baseline.json) was already re-ratified 2026-05-28
(de4399d); this brings the compile baseline back in sync.

Corrects the record: the #44 cycle-close audit body (7321826) wrongly
attributed the compile_check exit-1 to transient machine load. main is
sacrosanct so 7321826 cannot be amended; #45 and this commit are the
forward correction.

Verified: compile_check.py -n5 -> 24 metrics, 0 regressed, 24 stable.

bench/baseline_compile.json

@@ -1,105 +1,105 @@
 {
   "version": 1,
-  "captured": "2026-05-15",
+  "captured": "2026-05-30",
   "captured_via": "bench/compile_check.py",
   "note": "Compile-time bench. `check_ms` is `ail check FILE`; `build_O0_ms` is `ail build --opt=-O0 FILE`. Wall-clock includes subprocess spawn (~5-10 ms on Linux) and, for build, the clang link step. Tolerances are tuned for noise on a quiet developer machine, not as the language correctness bar.",
   "check_ms": {
     "hello": {
-      "baseline_ms": 1.78,
+      "baseline_ms": 2.41,
       "tolerance_pct": 25
     },
     "list_map_poly": {
-      "baseline_ms": 1.96,
+      "baseline_ms": 2.74,
       "tolerance_pct": 25
     },
     "local_rec_capture": {
-      "baseline_ms": 1.87,
+      "baseline_ms": 2.64,
       "tolerance_pct": 25
     },
     "borrow_own_demo": {
-      "baseline_ms": 1.87,
+      "baseline_ms": 2.65,
       "tolerance_pct": 25
     },
     "nested_pat": {
-      "baseline_ms": 3.32,
+      "baseline_ms": 4.66,
       "tolerance_pct": 25
     },
     "bench_list_sum": {
-      "baseline_ms": 1.99,
+      "baseline_ms": 2.75,
       "tolerance_pct": 25
     },
     "bench_tree_walk": {
-      "baseline_ms": 1.93,
+      "baseline_ms": 2.69,
       "tolerance_pct": 25
     },
     "bench_closure_chain": {
-      "baseline_ms": 1.96,
+      "baseline_ms": 2.66,
       "tolerance_pct": 25
     },
     "bench_hof_pipeline": {
-      "baseline_ms": 2.01,
+      "baseline_ms": 2.81,
       "tolerance_pct": 25
     },
     "bench_compute_intsum": {
-      "baseline_ms": 1.84,
+      "baseline_ms": 2.61,
       "tolerance_pct": 25
     },
     "bench_compute_collatz": {
-      "baseline_ms": 1.94,
+      "baseline_ms": 2.62,
       "tolerance_pct": 25
     },
     "bench_list_sum_explicit": {
-      "baseline_ms": 2.04,
+      "baseline_ms": 2.82,
       "tolerance_pct": 25
     }
   },
   "build_O0_ms": {
     "hello": {
-      "baseline_ms": 90.78,
+      "baseline_ms": 100.07,
       "tolerance_pct": 20
     },
     "list_map_poly": {
-      "baseline_ms": 93.63,
+      "baseline_ms": 103.14,
       "tolerance_pct": 20
     },
     "local_rec_capture": {
-      "baseline_ms": 93.13,
+      "baseline_ms": 102.03,
       "tolerance_pct": 20
     },
     "borrow_own_demo": {
-      "baseline_ms": 92.56,
+      "baseline_ms": 102.71,
       "tolerance_pct": 20
     },
     "nested_pat": {
-      "baseline_ms": 97.36,
+      "baseline_ms": 107.33,
       "tolerance_pct": 20
     },
     "bench_list_sum": {
-      "baseline_ms": 93.93,
+      "baseline_ms": 104.09,
       "tolerance_pct": 20
     },
     "bench_tree_walk": {
-      "baseline_ms": 94.0,
+      "baseline_ms": 102.01,
       "tolerance_pct": 20
     },
     "bench_closure_chain": {
-      "baseline_ms": 93.06,
+      "baseline_ms": 103.84,
       "tolerance_pct": 20
     },
     "bench_hof_pipeline": {
-      "baseline_ms": 94.59,
+      "baseline_ms": 103.74,
       "tolerance_pct": 20
     },
     "bench_compute_intsum": {
-      "baseline_ms": 91.65,
+      "baseline_ms": 101.15,
       "tolerance_pct": 20
     },
     "bench_compute_collatz": {
-      "baseline_ms": 93.36,
+      "baseline_ms": 102.45,
       "tolerance_pct": 20
     },
     "bench_list_sum_explicit": {
-      "baseline_ms": 94.03,
+      "baseline_ms": 103.0,
       "tolerance_pct": 20
     }
   }