Sprint 63: Learned Adapter Hints (Non-Authoritative) — Steps 859-868

Implements the learned adapter hints layer with governance guardrails:
- HintFeatureExtractor: extract features from decision ledgers (step 859)
- HintModelInterface: pair-specific hint query interface (step 860)
- DeterministicFallback: safe fallback when hints unavailable (step 861)
- HintConfidencePacket: confidence bands and escalation logic (step 862)
- HintABHarness: A/B harness to measure hint effectiveness (step 863)
- HintRollbackControl: suppress and lift hint suppression per pair (step 864)
- whetstone_get_adapter_hints MCP tool (step 865)
- whetstone_set_hint_policy MCP tool (step 866)
- HintSafetyGuardrails: non-authoritative enforcement + audit (step 867)
- Sprint63IntegrationSummary (step 868)

All 10 steps passing (94 tests). Governance rule: learned hints may
suggest; deterministic policy decides.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

editor/tests/step862_test.cpp

@@ -0,0 +1,47 @@
+// Step 862: Hint confidence + uncertainty packet format (10 tests)
+#include "graduation/HintConfidencePacket.h"
+#include <iostream>
+static int p=0,f=0;
+#define T(n) { std::cout << "  " << #n << "... "; }
+#define P() { std::cout << "PASS\n"; ++p; }
+#define F(m) { std::cout << "FAIL: " << m << "\n"; ++f; }
+#define C(c,m) if(!(c)){F(m);return;}
+
+void t1(){T(hint_id_set);
+    auto p2=HintConfidencePacketModel::make("H-1",0.9f,0.1f,"model");
+    C(p2.hintId=="H-1","id");P();}
+void t2(){T(confidence_stored);
+    auto p2=HintConfidencePacketModel::make("H-1",0.75f,0.1f,"model");
+    C(p2.confidence==0.75f,"conf");P();}
+void t3(){T(band_high);
+    auto p2=HintConfidencePacketModel::make("H-1",0.9f,0.1f,"m");
+    C(p2.confidenceBand=="high","high");P();}
+void t4(){T(band_medium);
+    auto p2=HintConfidencePacketModel::make("H-1",0.65f,0.1f,"m");
+    C(p2.confidenceBand=="medium","medium");P();}
+void t5(){T(band_low);
+    auto p2=HintConfidencePacketModel::make("H-1",0.3f,0.1f,"m");
+    C(p2.confidenceBand=="low","low");P();}
+void t6(){T(band_unknown);
+    auto p2=HintConfidencePacketModel::make("H-1",0.1f,0.1f,"m");
+    C(p2.confidenceBand=="unknown","unknown");P();}
+void t7(){T(escalate_high_uncertainty);
+    auto p2=HintConfidencePacketModel::make("H-1",0.9f,0.6f,"m");
+    C(p2.shouldEscalate,"escalate");P();}
+void t8(){T(no_escalate_normal);
+    auto p2=HintConfidencePacketModel::make("H-1",0.9f,0.1f,"m");
+    C(!p2.shouldEscalate,"no esc");P();}
+void t9(){T(escalate_low_confidence);
+    auto p2=HintConfidencePacketModel::make("H-1",0.2f,0.1f,"m");
+    C(p2.shouldEscalate,"esc low conf");P();}
+void t10(){T(to_json_has_band);
+    auto p2=HintConfidencePacketModel::make("H-1",0.9f,0.1f,"m");
+    auto j=HintConfidencePacketModel::toJson(p2);
+    C(j.contains("band"),"band");P();}
+
+int main(){
+    std::cout<<"Step 862: Hint confidence + uncertainty packet\n";
+    t1();t2();t3();t4();t5();t6();t7();t8();t9();t10();
+    std::cout<<"\nResults: "<<p<<"/"<<(p+f)<<" passed\n";
+    return f?1:0;
+}