reset to pre-modification baseline; restart feature work from clean state

Restoring the working tree to the pristine pre-Claude baseline previously
preserved at /data/clearpilot (now /data/clearpilot-baseline). The prior
modified-but-broken tree is snapshotted at /data/openpilot-broken-2026-05-03
and tagged here as pre-reset-2026-05-03 for reference.

From here, features (UI changes, dashcam, telemetry, GPS, display modes,
speed logic, standstill power saving, etc.) will be re-introduced one at
a time with proper testing.

build_preflight.sh

@@ -1,11 +0,0 @@
-#!/usr/bin/bash
-# CLEARPILOT: build preflight — create directories and fix state that
-# git cannot track but the build requires.  Called by build_only.sh and
-# launch_chffrplus.sh before scons runs.
-
-BASEDIR="${BASEDIR:-/data/openpilot}"
-
-# SConscript files write generated headers into obj/ directories at
-# parse time — these must exist before scons starts.
-mkdir -p "$BASEDIR/body/board/obj"
-mkdir -p "$BASEDIR/panda/board/obj"