gander: migrate library CLI activation to tester socket

agents/gander/work/queue-196/BUILD.md

@@ -105,3 +105,5 @@ changes are planned before the batch. M1-M29 remain prepared and unexecuted.
 
 2026-10-21 sage-2072 product test: added the merge-scoped SSO/socket conversion case without --send, asserting pointer argv order, rendered unit argv order, status agreement and no secret-file reads. Removing socket from sso_for_target is its planned RED case (M28b). Focused RED/GREEN remains pending the busy gate: Herb's suite was active at the preflight, so no test started. Runtime code unchanged. Mos mos-1197 owner-subject ruling recorded in queue-252/BUILD-NOTES.md.
 2026-10-21 sage-2072/2077 driver: unique string-target guard preflights every definition before any tests and before creating scratch state; M28 names without_proof, M28b names kept, M5 names the parse catch, M25 names append flags, M29 uses the unique full line. Static audit accepts all 30 definitions; zero/duplicate targets refuse. Against 64539c96b, M5 old/narrowed bytes match; M25 differs and joins the next batch. No mutation tests ran in this static check.
+
+2026-10-21 mos-1198 r5: row 215 landed ahead of row 196; its library CLI fixture retained --tester-port, a semantic conflict despite the callback code merging. The sole test change switches activation to --tester-socket. The test name and every original assertion remain byte-identical; the existing startServer hook still captures both listener callback pairs. No product file changed. No test run before Sage's fourth-run grant; Duckworth reviews this hunk.

packages/webui/tests/library-cli.test.mjs

@@ -22,7 +22,7 @@ test('C2-04 CLI: both listener callback pairs dispatch library verbs with their
       return next(url,context);
     }});`);
   const result = spawnSync(process.execPath, [new URL('../src/cli.mjs', import.meta.url).pathname,
-    'serve', '--business', 'acme', '--port', '0', '--tester-port', '7444'],
+    'serve', '--business', 'acme', '--port', '0', '--tester-socket'],
     { env: { ...f.env, NODE_OPTIONS: `--import=${hook}` }, encoding: 'utf8', timeout: 10000 });
   assert.equal(result.status, 0, result.stdout + result.stderr);
   const calls = readFileSync(log, 'utf8').trim().split('\n').filter(Boolean).map(JSON.parse);