fix: bump spawn-test timeouts to avoid CI flakiness (closes #12)

The crashed/exited/stderr spawn tests used 0.3-0.5s timeouts. On a slow CI
runner, interpreter startup can exceed that, so the process is still starting
when the timeout fires, gets killed, and is misclassified "ok" (still running)
instead of "crashed"/"exited". Bump those three to 2.0s. The two "ok" paths
(sleep-60, stdin-block) stay at 0.3s since timing out there means success.

tests/test_core.py

@@ -256,17 +256,20 @@ def test_spawn_test_ok_still_running():
 
 
 def test_spawn_test_crashed():
-    # A process that exits with a non-zero code immediately
+    # A process that exits with a non-zero code immediately.
+    # Timeout is generous (not 0.3s) so a slow CI runner's interpreter startup
+    # can't outlast it and misclassify the crash as "ok" (still running). See #12.
     r = c.spawn_test(
-        {"command": sys.executable, "args": ["-c", "raise SystemExit(1)"]}, timeout=0.3
+        {"command": sys.executable, "args": ["-c", "raise SystemExit(1)"]}, timeout=2.0
     )
     assert r["outcome"] == "crashed"
     assert r["returncode"] == 1
 
 
 def test_spawn_test_exited_cleanly():
-    # A process that exits 0 before timeout (unusual for a server)
-    r = c.spawn_test({"command": sys.executable, "args": ["-c", "pass"]}, timeout=0.5)
+    # A process that exits 0 before timeout (unusual for a server).
+    # Generous timeout so slow-runner startup can't flip this to "ok". See #12.
+    r = c.spawn_test({"command": sys.executable, "args": ["-c", "pass"]}, timeout=2.0)
     assert r["outcome"] == "exited"
     assert r["returncode"] == 0
 
@@ -288,7 +291,7 @@ def test_spawn_test_stderr_captured():
             "command": sys.executable,
             "args": ["-c", "import sys; sys.stderr.write('test-err\\n'); sys.exit(2)"],
         },
-        timeout=0.5,
+        timeout=2.0,
     )
     assert r["outcome"] == "crashed"
     assert "test-err" in r["stderr"]