Sprint 65: Parallel Pair Upgrades and Queue Optimization — Steps 879-888

Implements priority-aware pair-upgrade queue with starvation prevention:
- PairUpgradeQueue: enqueue/dequeue/getActive sorted by priority (step 879)
- UpgradePriorityPolicy: critical/revenue/coverage/experimental classes (step 880)
- ParallelDispatchOptimizer: schedule N pairs with blocked-pair constraints (step 881)
- StarvationPrevention: detect and promote starved pairs (step 882)
- QueueHealthScorer: stall-rate-based health scoring (step 883)
- RetryBackoffStrategy: exponential backoff with max-attempts guard (step 884)
- whetstone_enqueue_pair_upgrade MCP tool (step 885)
- whetstone_get_upgrade_queue MCP tool with priority sorting (step 886)
- UpgradeQueueObservabilityPanel: snapshot model for queue visibility (step 887)
- Sprint65IntegrationSummary (step 888)

All 10 steps passing (94 tests). Routing rule: critical-tier regressions
preempt all experimental upgrades.

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

editor/tests/step888_test.cpp

@@ -0,0 +1,24 @@
+// Step 888: Sprint65IntegrationSummary tests (8 tests)
+#include "Sprint65IntegrationSummary.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(sprintNumber);C(Sprint65IntegrationSummary::sprintNumber==65,"65");P();}
+void t2(){T(stepsCompleted);C(Sprint65IntegrationSummary::stepsCompleted==10,"10");P();}
+void t3(){T(theme_not_empty);C(std::string(Sprint65IntegrationSummary::theme).size()>0,"theme");P();}
+void t4(){T(verify_true);C(Sprint65IntegrationSummary::verify(),"verify");P();}
+void t5(){T(json_has_sprint_key);auto j=Sprint65IntegrationSummary::toJson();C(j.contains("sprint"),"sprint");P();}
+void t6(){T(json_sprint_65);auto j=Sprint65IntegrationSummary::toJson();C(j["sprint"]==65,"sprint=65");P();}
+void t7(){T(json_steps_10);auto j=Sprint65IntegrationSummary::toJson();C(j["steps"]==10,"steps=10");P();}
+void t8(){T(json_status_complete);auto j=Sprint65IntegrationSummary::toJson();C(j["status"]=="complete","complete");P();}
+
+int main(){
+    std::cout<<"Step 888: Sprint65IntegrationSummary\n";
+    t1();t2();t3();t4();t5();t6();t7();t8();
+    std::cout<<"\nResults: "<<p<<"/"<<(p+f)<<" passed\n";
+    return f?1:0;
+}