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.

selfdrive/manager/build.py

@@ -1,6 +1,5 @@
 #!/usr/bin/env python3
 import os
-import sys
 import subprocess
 from pathlib import Path
 
@@ -55,14 +54,6 @@ def build(spinner: Spinner, dirty: bool = False, minimal: bool = False) -> None:
 
     if scons.returncode == 0:
       Path('/data/openpilot/prebuilt').touch()
-
-      # CLEARPILOT: update prebuilt spinner if the new build is newer
-      new_spinner = Path(BASEDIR) / "selfdrive/ui/_spinner"
-      old_spinner = Path(BASEDIR) / "selfdrive/ui/qt/spinner"
-      if new_spinner.exists() and (not old_spinner.exists() or new_spinner.stat().st_mtime > old_spinner.stat().st_mtime):
-        import shutil
-        shutil.copy2(str(new_spinner), str(old_spinner))
-
       break
 
   if scons.returncode != 0:
@@ -78,13 +69,8 @@ def build(spinner: Spinner, dirty: bool = False, minimal: bool = False) -> None:
     # Show TextWindow
     spinner.close()
     if not os.getenv("CI"):
-      # CLEARPILOT: BUILD_ONLY mode shows error on screen but doesn't block
-      t = TextWindow("openpilot failed to build\n \n" + error_s)
-      if os.getenv("BUILD_ONLY"):
-        print(error_s, file=sys.stderr)
-      else:
+      with TextWindow("openpilot failed to build\n \n" + error_s) as t:
         t.wait_for_exit()
-        t.close()
     exit(1)
 
   # enforce max cache size