fix(test-infra): judge uses resolveClaudeBinary; eval:watch reads the real partials dir

judgePtyState spawned the bare string 'claude' three definitions below the
resolveClaudeBinary() helper this same file exports — broken under hermetic
PATHs where every other launch in the file resolves correctly.

eval:watch read _partial-e2e.json from the legacy global ~/.gstack-dev/evals/
while EvalCollector writes it into the per-project eval dir (or
GSTACK_EVAL_DIR) — so the dashboard's completed-tests panel was empty
whenever slug detection succeeded, i.e. the normal case. The heartbeat and
per-run progress logs stay global by design (session-runner.ts: 'heartbeat
stays global'). The three eval-CLI docstrings stop claiming the legacy dir
is the primary location.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

test/helpers/claude-pty-runner.ts

@@ -454,8 +454,11 @@ ${tail}
   };
 
   try {
+    // Use the same binary resolution as every PTY launch in this file —
+    // judgePtyState previously hardcoded bare 'claude' three definitions
+    // below resolveClaudeBinary(), breaking under hermetic PATHs.
     const result = nodeSpawnSync(
-      'claude',
+      resolveClaudeBinary() ?? 'claude',
       ['-p', '--model', 'claude-haiku-4-5', '--max-turns', '1'],
       {
         input: prompt,