Tiny: Enable P0→FC direct path for class7 (1KB) by default + docs

- Class7 (1KB): P0 direct-to-FastCache now default ON (HAKMEM_TINY_P0_DIRECT_FC_C7 unset or not '0').
- Keep A/B gates: HAKMEM_TINY_P0_ENABLE, HAKMEM_TINY_P0_DIRECT_FC (class5), HAKMEM_TINY_P0_DIRECT_FC_C7 (class7),
  HAKMEM_TINY_P0_DRAIN_THRESH (default 32), HAKMEM_TINY_P0_NO_DRAIN, HAKMEM_TINY_P0_LOG.
- P0 batch now supports class7 direct fill in addition to class5: gather (drain thresholded → freelist pop → linear carve)
  without writing into objects, then bulk-push into FC, update meta/active counters once.
- Docs: Update direct-FC defaults (class5+class7 ON) in docs/TINY_P0_BATCH_REFILL.md.

Notes
- Use tools/bench_rs_from_files.sh for RS(hakmem/system) to compare runs across CPUs.
- Next: parameter sweep for class7 (FC cap/batch limit/drain threshold) and perf counters A/B.

benchmarks/results/2025-11-09_ryzen7-5825U/SUMMARY.md

@@ -0,0 +1,19 @@
+CPU: Ryzen 7 5825U
+Date: 2025-11-09
+P0: ON (default)
+
+Tiny Random Mixed (100k, 1T)
+- 256B: hakmem=1:2749689 ops/s, system=1:65601947 ops/s
+- 1024B: hakmem=1:2576325 ops/s, system=1:68778109 ops/s
+
+
+
+Pool TLS (256B)
+- 1T (100k): hakmem=5:6266687 ops/s, system=5:6338090 ops/s
+- 4T (50k): hakmem=5:13360242 ops/s, system=5:13254552 ops/s
+
+
+
+Notes
+- RS = hakmem/system でCPU差を相殺した相対比較が可能。
+- 詳細ログは本フォルダ内 *.log を参照。

benchmarks/results/2025-11-09_ryzen7-5825U_c7_direct/SUMMARY_1KB.md

@@ -0,0 +1,8 @@
+CPU: Ryzen 7 5825U
+Date: 2025-11-09
+Class: 1KB (class7)
+
+hakmem OFF (direct=0): 10k=1:2406566 ops/s, 100k=1:2657404 ops/s
+hakmem ON  (direct=1): 10k= ops/s, 100k= ops/s
+system 100k: 1:64986168 ops/s
+