tools: add make analyze/test/doctor and unify gradle wrappers

- Add scripts/analyze_all.sh and scripts/test_all.sh that run flutter
  analyze/test across every app and report a summary
- Add scripts/repo_doctor.sh that flags config drift (sdk constraint,
  analysis_options, pubspec name, applicationId, gradle version, docs,
  tracked generated files) and exits non-zero for use as a pre-commit gate
- Wire these into the Makefile as 'make analyze/test/doctor' and document
  them in MAINTENANCE.md
- Bring bmi_calculator and push_notifications gradle wrappers up to the
  repo-standard 9.7.0; note push_notifications as a Firebase app requiring
  google-services.json

scripts/repo_doctor.sh

@@ -0,0 +1,104 @@
+#!/usr/bin/env bash
+set -uo pipefail
+
+# Reports repository drift across all example apps.
+# Run after adding or modifying an app, or before a release.
+# Exits non-zero if any issues are found.
+
+source "$(dirname "${BASH_SOURCE[0]}")/common.sh"
+
+STD_SDK='sdk: ">=3.0.0 <4.0.0"'
+GRADLE_MODE="9.7.0"
+
+issues=0
+
+report() {
+	local label="$1"
+	shift
+	if [ "$#" -eq 0 ]; then
+		return
+	fi
+	issues=1
+	echo ""
+	echo "  $label:"
+	for item in "$@"; do
+		printf "    %s\n" "$item"
+	done
+}
+
+collect() {
+	local label="$1"
+	shift
+	local found=()
+	for app in ./*; do
+		if [ -f "$app/pubspec.yaml" ]; then
+			local name
+			name=$(basename "$app")
+			"$@" "$app" "$name" && found+=("$name")
+		fi
+	done
+	report "$label" "${found[@]}"
+}
+
+check_sdk() {
+	local app="$1" name="$2"
+	! grep -qF "$STD_SDK" "$app/pubspec.yaml"
+}
+
+check_lints() {
+	local app="$1" name="$2"
+	[ ! -f "$app/analysis_options.yaml" ] || ! grep -q "flutter_lints" "$app/pubspec.yaml"
+}
+
+check_name() {
+	local app="$1" name="$2"
+	[ "$(grep -m1 '^name:' "$app/pubspec.yaml" | awk '{print $2}')" != "$name" ]
+}
+
+check_android_id() {
+	local app="$1" name="$2"
+	local f="$app/android/app/build.gradle.kts"
+	[ ! -f "$f" ] && return 1
+	! grep -q 'namespace = "github\.nisrulz\.' "$f"
+}
+
+check_gradle() {
+	local app="$1" name="$2"
+	local props="$app/android/gradle/wrapper/gradle-wrapper.properties"
+	[ ! -f "$props" ] && return 1
+	! grep -q "$GRADLE_MODE" "$props"
+}
+
+check_docs() {
+	local app="$1" name="$2"
+	! grep -q "(/$name)" documentation/EXAMPLES.md
+}
+
+separator
+echo "  Repository doctor:"
+echo "  Checking all apps for configuration drift."
+
+collect "Apps with a non-standard SDK constraint" check_sdk
+collect "Apps missing analysis_options.yaml or flutter_lints" check_lints
+collect "Apps whose pubspec name does not match the folder" check_name
+collect "Apps not using the github.nisrulz.* Android applicationId" check_android_id
+collect "Apps not on the standard Gradle version" check_gradle
+collect "Apps missing from documentation/EXAMPLES.md (run 'make docs')" check_docs
+
+# Tracked generated files that should not be in git.
+tracked_generated=$(git ls-files | grep -E "\.dart_tool/|GeneratedPluginRegistrant|\.flutter-plugins-dependencies|pubspec\.lock" || true)
+if [ -n "$tracked_generated" ]; then
+	issues=1
+	echo ""
+	echo "  Tracked generated files (remove with 'git rm --cached'):"
+	echo "$tracked_generated" | sed 's/^/    /'
+fi
+
+separator
+if [ "$issues" -eq 0 ]; then
+	echo "  All checks passed."
+else
+	echo "  Issues found. Fix them before committing."
+	exit 1
+fi
+separator