fix: the github-range runner throws so an orphaned BEFORE_SHA can fall back to dev

resolveValidationRange already knows how to replace a force-push-orphaned
BEFORE_SHA with origin/dev, but the CLI handed it a runner that killed the
process with exit 2 on the first cat-file instead of throwing into
gitObjectExists' catch. Every push after a mandatory issue-branch rebase
therefore painted process-gate red (runs 32939996348, 32940625718,
32942113142). The regression test drives the real CLI in a throwaway repo
with a BEFORE_SHA that no longer exists.

Issue: #315
User-Visible: no

scripts/process-gate.mjs

@@ -575,13 +575,20 @@ function main(argv) {
 
   let range = value('range');
   if (!range && flag('github-range')) {
+    // gitObjectExists ловит исключение, чтобы подменить осиротевший после
+    // force-push BEFORE_SHA на origin/dev (#315). Раннер обязан бросать,
+    // а не завершать процесс, как это делает git() ниже.
     range = resolveValidationRange({
       eventName: process.env.EVENT_NAME,
       beforeSha: process.env.BEFORE_SHA,
       baseSha: process.env.BASE_SHA,
       headSha: process.env.HEAD_SHA,
       developmentBranch: process.env.DEVELOPMENT_BRANCH,
-    }, (args) => git(args, repo).trim());
+    }, (args) => {
+      const r = spawnSync('git', ['-C', repo, ...args], { encoding: 'utf8' });
+      if (r.status !== 0) throw new Error(`git ${args.join(' ')} → ${(r.stderr || '').trim()}`);
+      return r.stdout.trim();
+    });
   }
   if (!range) {
     const hasDev = spawnSync('git', ['-C', repo, 'rev-parse', '--verify', 'origin/dev'],