Add Claude observability tracing and diagnostics UI

tests/claude-trace-store.test.ts

@@ -0,0 +1,42 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+import { mkdtemp, writeFile } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { filterClaudeTraceEvents, readClaudeTraceEvents } from "../src/ui/claude-trace-store.js";
+
+test("readClaudeTraceEvents parses and sorts ndjson records", async () => {
+  const workspace = await mkdtemp(join(tmpdir(), "claude-trace-store-"));
+  const logPath = join(workspace, "claude-trace.ndjson");
+  await writeFile(
+    logPath,
+    [
+      '{"timestamp":"2026-02-24T17:27:05.000Z","message":"later","sessionId":"s1"}',
+      'not-json',
+      '{"timestamp":"2026-02-24T17:26:00.000Z","message":"earlier","sessionId":"s1"}',
+      '{"message":"missing timestamp"}',
+    ].join("\n"),
+    "utf8",
+  );
+
+  const events = await readClaudeTraceEvents(logPath);
+  assert.equal(events.length, 2);
+  assert.equal(events[0]?.message, "earlier");
+  assert.equal(events[1]?.message, "later");
+});
+
+test("filterClaudeTraceEvents filters by session and limit", () => {
+  const events = [
+    { timestamp: "2026-02-24T17:00:00.000Z", message: "a", sessionId: "s1" },
+    { timestamp: "2026-02-24T17:01:00.000Z", message: "b", sessionId: "s2" },
+    { timestamp: "2026-02-24T17:02:00.000Z", message: "c", sessionId: "s1" },
+  ];
+
+  const filtered = filterClaudeTraceEvents(events, {
+    sessionId: "s1",
+    limit: 1,
+  });
+
+  assert.equal(filtered.length, 1);
+  assert.equal(filtered[0]?.message, "c");
+});