feat: D16 adjudication — 2v2 stays hypothesis until a rule fires.

temporal_freshness then authority_pairing; unresolved keeps (not confirmed).
bin/facts/audit contradict. Gitea #29.

internal/facts/contradict_test.go

@@ -0,0 +1,86 @@
+package facts
+
+import "testing"
+
+func src(id, kind string, stale bool) Source {
+	return Source{ID: id, Kind: kind, Stale: stale}
+}
+
+func TestTwoVsTwoStaysHypothesis(t *testing.T) {
+	c := Claim{
+		Text: "svc listens on 443",
+		Yes: []Source{
+			src("docker-ps", KindRuntime, false),
+			src("compose", KindConfig, false),
+		},
+		No: []Source{
+			src("docker-ps-old", KindRuntime, false),
+			src("compose-old", KindConfig, false),
+		},
+	}
+	r := Adjudicate(c)
+	if r.Confirmed || r.Confidence != ConfHypothesis || r.Rule != RuleUnresolved {
+		t.Fatalf("2v2 must stay (not confirmed): %+v", r)
+	}
+	if r.Winner != "" {
+		t.Fatalf("unresolved must not name a winner: %+v", r)
+	}
+}
+
+func TestTemporalFreshnessResolvesStaleSide(t *testing.T) {
+	c := Claim{
+		Text: "svc listens on 443",
+		Yes: []Source{
+			src("docker-ps", KindRuntime, false),
+			src("compose", KindConfig, false),
+		},
+		No: []Source{
+			src("old-readme", KindNarrative, true),
+			src("old-wiki", KindNarrative, true),
+		},
+	}
+	r := Adjudicate(c)
+	if !r.Confirmed || r.Rule != RuleTemporalFreshness || r.Winner != "yes" {
+		t.Fatalf("fresh yes vs stale no: %+v", r)
+	}
+}
+
+func TestAuthorityPairingBeatsNarrative(t *testing.T) {
+	c := Claim{
+		Text: "svc listens on 443",
+		Yes: []Source{
+			src("docker-ps", KindRuntime, false),
+			src("compose", KindConfig, false),
+		},
+		No: []Source{
+			src("readme", KindNarrative, false),
+			src("wiki", KindNarrative, false),
+		},
+	}
+	r := Adjudicate(c)
+	if !r.Confirmed || r.Rule != RuleAuthorityPairing || r.Winner != "yes" {
+		t.Fatalf("A×B vs C×C: %+v", r)
+	}
+}
+
+func TestTwoSourceYesIsConfirmed(t *testing.T) {
+	c := Claim{
+		Text: "arc-1 runs Matrix",
+		Yes: []Source{
+			src("compose", KindConfig, false),
+			src("docker-ps", KindRuntime, false),
+		},
+	}
+	r := Adjudicate(c)
+	if !r.Confirmed || r.Rule != RuleTwoSource || r.Winner != "yes" {
+		t.Fatalf("%+v", r)
+	}
+}
+
+func TestSingleSourceIsHypothesis(t *testing.T) {
+	c := Claim{Text: "maybe", Yes: []Source{src("readme", KindNarrative, false)}}
+	r := Adjudicate(c)
+	if r.Confirmed || r.Rule != RuleSingleSource {
+		t.Fatalf("%+v", r)
+	}
+}