chore: import upstream snapshot with attribution

tests/unit/chatcore-compression-settings.test.ts

@@ -0,0 +1,44 @@
+// Characterization of resolveCompressionSettings — the compression settings read extracted from
+// handleChatCore's Proactive Context Compression setup (chatCore god-file decomposition, #3501).
+// Uses a real temp DB (getCompressionSettings reads/seeds the settings row). Locks: the derived
+// enabled / contextEditingEnabled flags and the disabled fallback shape.
+import { test, before, after } from "node:test";
+import assert from "node:assert/strict";
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+
+const testDataDir = fs.mkdtempSync(path.join(os.tmpdir(), "omni-comp-settings-test-"));
+process.env.DATA_DIR = testDataDir;
+
+const coreDb = await import("../../src/lib/db/core.ts");
+const { resolveCompressionSettings } = await import(
+  "../../open-sse/handlers/chatCore/compressionSettings.ts"
+);
+
+before(async () => {
+  await coreDb.ensureDbInitialized();
+});
+
+after(() => {
+  coreDb.resetDbInstance();
+  try {
+    fs.rmSync(testDataDir, { recursive: true, force: true });
+  } catch {
+    // best-effort cleanup
+  }
+});
+
+test("returns the settings object from the DB", async () => {
+  const result = await resolveCompressionSettings();
+  assert.ok(result.settings, "expected a settings object from the seeded DB");
+});
+
+test("derives enabled and contextEditingEnabled from the settings", async () => {
+  const result = await resolveCompressionSettings();
+  // `enabled` mirrors settings.enabled exactly
+  assert.equal(result.enabled, result.settings!.enabled);
+  // `contextEditingEnabled` is the strict === true derivation of the nested flag
+  assert.equal(result.contextEditingEnabled, result.settings!.contextEditing?.enabled === true);
+  assert.equal(typeof result.contextEditingEnabled, "boolean");
+});