Add LED tool: device, CLI, web UI, build scripts, and tests

- device.py: device communication/handling
- cli.py: CLI interface updates
- web.py: web interface
- build.py, build.sh, install.sh: build and install scripts
- Pipfile: Python dependencies
- lib/mpremote: mpremote library
- test_*.py: import and LED tests
- Updated .gitignore and README

Co-authored-by: Cursor <cursoragent@cursor.com>

lib/mpremote/mp_errno.py

@@ -0,0 +1,55 @@
+import errno
+import platform
+
+# This table maps numeric values defined by `py/mperrno.h` to host errno code.
+MP_ERRNO_TABLE = {
+    1: errno.EPERM,
+    2: errno.ENOENT,
+    3: errno.ESRCH,
+    4: errno.EINTR,
+    5: errno.EIO,
+    6: errno.ENXIO,
+    7: errno.E2BIG,
+    8: errno.ENOEXEC,
+    9: errno.EBADF,
+    10: errno.ECHILD,
+    11: errno.EAGAIN,
+    12: errno.ENOMEM,
+    13: errno.EACCES,
+    14: errno.EFAULT,
+    16: errno.EBUSY,
+    17: errno.EEXIST,
+    18: errno.EXDEV,
+    19: errno.ENODEV,
+    20: errno.ENOTDIR,
+    21: errno.EISDIR,
+    22: errno.EINVAL,
+    23: errno.ENFILE,
+    24: errno.EMFILE,
+    25: errno.ENOTTY,
+    26: errno.ETXTBSY,
+    27: errno.EFBIG,
+    28: errno.ENOSPC,
+    29: errno.ESPIPE,
+    30: errno.EROFS,
+    31: errno.EMLINK,
+    32: errno.EPIPE,
+    33: errno.EDOM,
+    34: errno.ERANGE,
+    95: errno.EOPNOTSUPP,
+    97: errno.EAFNOSUPPORT,
+    98: errno.EADDRINUSE,
+    103: errno.ECONNABORTED,
+    104: errno.ECONNRESET,
+    105: errno.ENOBUFS,
+    106: errno.EISCONN,
+    107: errno.ENOTCONN,
+    110: errno.ETIMEDOUT,
+    111: errno.ECONNREFUSED,
+    113: errno.EHOSTUNREACH,
+    114: errno.EALREADY,
+    115: errno.EINPROGRESS,
+    125: errno.ECANCELED,
+}
+if platform.system() != "Windows":
+    MP_ERRNO_TABLE[15] = errno.ENOTBLK