add libjpeg-turbo package (#15)

Vendors libjpeg-turbo 3.1.0 as a static library for openpilot, following
the same pattern as zstd/ncurses/zeromq.

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

libjpeg/libjpeg/__init__.py

@@ -0,0 +1,10 @@
+import os
+
+DIR = os.path.join(os.path.dirname(__file__), "install")
+LIB_DIR = os.path.join(DIR, "lib")
+INCLUDE_DIR = os.path.join(DIR, "include")
+
+
+def smoketest():
+  assert os.path.isfile(os.path.join(LIB_DIR, "libjpeg.a")), "libjpeg.a not found"
+  assert os.path.isfile(os.path.join(INCLUDE_DIR, "jpeglib.h")), "jpeglib.h not found"