fix(#2089): widen read-injection-scanner property test timeout to avoid node22 race

The property test's execFileSync timeout (5000ms) was identical to the
scanner's own internal stdin-timeout (hooks/gsd-read-injection-scanner.js:109,
also 5000ms). Under concurrent test-chunk load on linux-node22 — which #2089's
3 new cursor test files redistribute — the scanner subprocess's stdin 'end'
event can fire late enough that execFileSync's SIGTERM arrives before the
scanner's own process.exit(0), producing err.status=null → exitCode=1 →
spurious property-test failure.

The scanner has no process.exit(N!=0) paths; the only non-zero exit is from
the signal-kill race. Doubling the test ceiling to 10000ms gives the scanner's
5000ms internal exit a 5s buffer to win the race deterministically on every
node version.

tests/read-injection-scanner.property.test.cjs

@@ -27,7 +27,14 @@ function runHook(payload) {
     const stdout = execFileSync(process.execPath, [HOOK_PATH], {
       input: JSON.stringify(payload),
       encoding: 'utf-8',
-      timeout: 5000,
+      // 10s — double the scanner's own 5s internal stdin-timeout
+      // (hooks/gsd-read-injection-scanner.js:109). Under concurrent test
+      // load (crowded run-tests.cjs chunks), node22's event-loop scheduling
+      // can delay the scanner's stdin 'end' handler past 5s, racing the
+      // scanner's process.exit(0) against this timeout's SIGTERM. A 10s
+      // ceiling gives the scanner's own 5s exit a 5s buffer to win the race
+      // deterministically on every node version. (#2089)
+      timeout: 10000,
       stdio: ['pipe', 'pipe', 'pipe'],
     });
     return { exitCode: 0, stdout: stdout.trim() };