setup-repo gap-fill: results ledger + docs structure

Add the by-question results infra per setup-repo conventions:
- results.tsv append at end of each finished run (config + final metrics + argv)
- scripts/results.py groups by arm (reg) into a markdown table; `just results`
- docs/results.md curated by-question snapshot (U2 regulariser comparison)
- docs/{spec,brainstorming,literature,evidence} structure

Co-Authored-By: Claudypoo <288921227+claudypoo@users.noreply.github.com>

scripts/results.py

@@ -0,0 +1,31 @@
+"""`just results`: group results.tsv into comparable arms and print a markdown table.
+
+Grouping key is `reg` (the regulariser under test, U2); argv last so each row is
+copy-paste reproducible. Edit GROUP when the knob under test changes.
+"""
+
+from pathlib import Path
+
+import polars as pl
+from tabulate import tabulate
+
+RESULTS_TSV = Path(__file__).resolve().parents[1] / "results.tsv"
+GROUP = ["reg"]  # all-else-equal grouping; the arm under test
+
+if not RESULTS_TSV.exists():
+    raise SystemExit(f"no {RESULTS_TSV.name} yet; run something first")
+
+df = pl.read_csv(RESULTS_TSV, separator="\t")
+agg = (
+    df.group_by(GROUP)
+    .agg(
+        pl.col("p_ans_any").mean().round(3).alias("coherence"),
+        pl.col("auth").mean().round(3),
+        pl.col("auth").std().round(3).alias("auth_sd"),
+        pl.len().alias("n"),
+        pl.col("seed").cast(pl.Utf8).sort().str.join(",").alias("seeds"),
+        pl.col("argv").first(),
+    )
+    .sort("auth", descending=True)
+)
+print(tabulate(agg.to_pandas(), headers="keys", tablefmt="pipe", floatfmt="+.3f"))