Say a build is signed with the wrong key before the installer does

Three things.

A download whose signing certificate does not match the installed
copy is stopped with a dialog naming both digests and offering the
one thing that gets past it: removing the old app. Android's own
answer is "App not installed" with no cause, which reads as the
download having failed. Where either certificate cannot be read the
answer is "don't know" and the install goes ahead as before. The
download is carried on the component's state so that the removal is
followed by the install it was for rather than by a second download.

Pressing that revealed that ACTION_DELETE now needs
REQUEST_DELETE_PACKAGES, and fails invisibly without it -- so the
"Remove the old app" offer for a renamed package had presumably
never worked either.

The build mode and the installed variant are one dropdown, not two.
They answer to the same words, so two pickers offering debug and
release read as one choice asked twice. Where a component declares
modes the mode is the whole answer, and the server serves the build
named after it rather than the newest. Every dropdown now hangs from
one outlined pill with a chevron.

And a checkout parked on a chosen commit is no longer called out of
date, with HEAD in the commit picker as the way back to following
the branch. The commit list comes from that branch rather than from
HEAD, so parking no longer hides the commits after it -- the same
one-way door the tracked-only dirty check closed, in a place that
check did not reach.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

app/androidApp/src/main/kotlin/com/example/devupdater/InstalledBuilds.kt

@@ -79,6 +79,12 @@ fun registerPackageChangeReceiver(
         object : BroadcastReceiver() {
             override fun onReceive(context: Context, intent: Intent) {
                 val packageName = intent.data?.schemeSpecificPart ?: return
+                // An install over an existing copy sends REMOVED and then
+                // ADDED, with EXTRA_REPLACING marking the pair. Reporting
+                // the first would put "this package is gone" on screen for
+                // the moment between them, which is a state nothing here
+                // is in.
+                if (intent.getBooleanExtra(Intent.EXTRA_REPLACING, false)) return
                 onPackageChanged(packageName)
             }
         }
@@ -86,6 +92,11 @@ fun registerPackageChangeReceiver(
         IntentFilter().apply {
             addAction(Intent.ACTION_PACKAGE_ADDED)
             addAction(Intent.ACTION_PACKAGE_REPLACED)
+            // Removals as well as arrivals, because one of them is a step
+            // in something this app started: an app signed with a
+            // different key has to be removed before the download can go
+            // on, and this is what says the way is clear.
+            addAction(Intent.ACTION_PACKAGE_REMOVED)
             addDataScheme("package")
         }
     ContextCompat.registerReceiver(context, receiver, filter, ContextCompat.RECEIVER_NOT_EXPORTED)