test(preload): strip the Capy launch markers so a direct bun test matches the shard sandbox

Red Team finding: the launch-marker scrub lived only in createShardSandbox,
so a direct `bun test <file>` run under an unattended Capy session inherited
GSTACK_SESSION_KIND, GSTACK_CAPY, GSTACK_EPHEMERAL and GSTACK_INSTALL_VERDICT
(GSTA-99's symptom). The preload now deletes the same four names, and
test/shard-engine.test.ts imports CAPY_LAUNCH_MARKERS instead of re-typing them.

Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>

test-setup.ts

@@ -33,6 +33,11 @@ for (const name of ['GSTACK_STATE_ROOT', 'GSTACK_STATE_DIR']) {
   delete process.env[name];
   process.stderr.write(`test-setup: stripped inherited ${name}; tests isolate state via GSTACK_HOME\n`);
 }
+// The Capy installer's launch markers (GSTA-99, GSTA-104): a focused `bun test`
+// run from a shell that sourced the launch file would hand every product child
+// an unattended Capy session it never set up. The shard engine strips the same
+// list for the lanes; this reaches direct runs too.
+for (const name of ['GSTACK_SESSION_KIND', 'GSTACK_CAPY', 'GSTACK_EPHEMERAL', 'GSTACK_INSTALL_VERDICT']) delete process.env[name];
 process.env.GSTACK_TEST_LEGACY_ROOT = path.join(os.tmpdir(), `gstack-test-legacy-root-${process.pid}-${Date.now()}-unused`);
 // Workflow leases (bin/gstack-lease) default to the installation's git dir;
 // for the dev checkout under test that is this repo's .git, and a live test

test/shard-engine.test.ts

@@ -24,6 +24,7 @@ import {
   strictShardStatus,
   writeDurationSeed,
   zeroExecutionVerdict,
+  CAPY_LAUNCH_MARKERS,
 } from '../scripts/lib/shard-engine';
 import { FREE_LANE_POLICY, exitCodeFor, runFreeShard } from '../scripts/test-free-shards';
 import {
@@ -252,7 +253,7 @@ describe('shard engine: capture and isolation', () => {
       for (const box of [a, b]) {
         expect(box.env.KEEP).toBe('1');
         expect(box.env.GSTACK_HOME).toBeUndefined();
-        for (const key of ['GSTACK_SESSION_KIND', 'GSTACK_CAPY', 'GSTACK_EPHEMERAL', 'GSTACK_INSTALL_VERDICT']) expect(box.env[key]).toBeUndefined();
+        for (const key of CAPY_LAUNCH_MARKERS) expect(box.env[key]).toBeUndefined();
         expect(box.env.GSTACK_STATE_ROOT).toBe('/kept-root');
         for (const key of ['TMPDIR', 'TEMP', 'TMP']) expect(box.env[key]).toBe(box.tmp);
         expect(box.env.CHROMIUM_PROFILE).toBe(path.join(box.stateDir, 'chromium-profile'));