Sprint 277: LSP Advanced Orchestration (steps 1913-1917)

- LSPWorkspaceIndex: track open docs, URI→{languageId,content,version}
- LSPDiagnosticsAggregator: merge diagnostics from multiple LSP sources per URI
- LSPCompletionMerger: merge+deduplicate completion items from multiple sources
- LSPOrchestrator: top-level coordinator composing all three + proxy + cross-lang resolver
- Sprint277IntegrationSummary: poly-api (Go+TypeScript) end-to-end integration

26/26 tests passing (5+5+5+5+6). All new headers ≤600 lines.
LoRA recorded: sprint277-2026-03-01 (1 call, 569 tokens).

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

editor/tests/step1915_test.cpp

@@ -0,0 +1,106 @@
+// Step 1915: LSPCompletionMerger
+// Collects CompletionItem lists from multiple sources; deduplicates by label.
+//
+//  t1: addItems and getItems from one source
+//  t2: two sources with disjoint labels → both present
+//  t3: two sources with overlapping label → deduplicated
+//  t4: clearSource removes one source without affecting others
+//  t5: clearAll empties; uniqueCount and sourceCount
+
+#include "LSPCompletionMerger.h"
+#include <iostream>
+#include <string>
+
+namespace ws = whetstone;
+
+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;}
+
+static ws::CompletionItem ci(const std::string& label, int kind,
+                              const std::string& detail,
+                              const std::string& src) {
+    ws::CompletionItem i; i.label=label; i.kind=kind; i.detail=detail; i.source=src; return i;
+}
+
+void t1(){
+    T(addItems_and_getItems_one_source);
+    ws::LSPCompletionMerger m;
+    m.addItems("gopls", { ci("fmt.Println", 3, "func", "gopls"),
+                          ci("fmt.Printf",  3, "func", "gopls") });
+    auto items = m.getItems();
+    C(items.size() == 2, "two items");
+    // sorted by label: fmt.Printf < fmt.Println
+    C(items[0].label == "fmt.Printf",  "first item sorted");
+    C(items[1].label == "fmt.Println", "second item sorted");
+    C(m.sourceCount() == 1, "one source");
+    P();
+}
+
+void t2(){
+    T(two_sources_disjoint_labels);
+    ws::LSPCompletionMerger m;
+    m.addItems("gopls",    { ci("fmt.Println", 3, "func", "gopls") });
+    m.addItems("tsserver", { ci("console.log", 3, "func", "tsserver") });
+    auto items = m.getItems();
+    C(items.size() == 2,                   "two items total");
+    C(m.uniqueCount() == 2,               "uniqueCount 2");
+    bool hasGo = false, hasTs = false;
+    for (auto& i : items) {
+        if (i.label == "fmt.Println") hasGo = true;
+        if (i.label == "console.log") hasTs = true;
+    }
+    C(hasGo && hasTs, "both items present");
+    P();
+}
+
+void t3(){
+    T(overlap_deduplicated_first_source_wins);
+    ws::LSPCompletionMerger m;
+    // Both offer "sort" — first by map key order ("gopls" < "tsserver") wins
+    m.addItems("gopls",    { ci("sort", 3, "from-go",   "gopls") });
+    m.addItems("tsserver", { ci("sort", 3, "from-ts",   "tsserver"),
+                             ci("split",3, "from-ts",   "tsserver") });
+    auto items = m.getItems();
+    C(items.size() == 2,              "two unique items");
+    C(items[0].label == "sort",       "sort present");
+    C(items[0].source == "gopls",     "gopls won duplicate");
+    C(items[1].label == "split",      "split present");
+    P();
+}
+
+void t4(){
+    T(clearSource_removes_one_source);
+    ws::LSPCompletionMerger m;
+    m.addItems("gopls",    { ci("fmt.Println", 3, "func", "gopls") });
+    m.addItems("tsserver", { ci("console.log", 3, "func", "tsserver") });
+    m.clearSource("gopls");
+    auto items = m.getItems();
+    C(items.size() == 1,                   "one item after clear");
+    C(items[0].label == "console.log",     "ts item remains");
+    C(m.sourceCount() == 1,               "one source remains");
+    P();
+}
+
+void t5(){
+    T(clearAll_and_counts);
+    ws::LSPCompletionMerger m;
+    m.addItems("a", { ci("alpha",1,"","a"), ci("beta",1,"","a") });
+    m.addItems("b", { ci("gamma",1,"","b") });
+    C(m.uniqueCount()  == 3, "unique 3");
+    C(m.sourceCount()  == 2, "sources 2");
+    m.clearAll();
+    C(m.uniqueCount()  == 0, "unique 0 after clearAll");
+    C(m.sourceCount()  == 0, "sources 0 after clearAll");
+    C(m.getItems().empty(),  "empty after clearAll");
+    P();
+}
+
+int main(){
+    std::cout << "Step 1915: LSPCompletionMerger\n";
+    t1(); t2(); t3(); t4(); t5();
+    std::cout << "\n" << p << "/" << (p+f) << " passed\n";
+    return f > 0 ? 1 : 0;
+}