build(release): several apps released in one run (train:minor learn), their version commits pushed without the checks

The release tool and tool/with_signing_keys.sh take several apps, each with its version
after a colon or none, and release them one after another, each as alone, stopping at
the first that fails; the key script fetches every named app's key.

The pre-push hook skips tool/check.dart when a push brings release commits alone: the
release tool's chore(release) subject, an app's pubspec changed in its version line and
its texts of what's new, nothing else (tool/release_push.dart). Signatures are checked as
before, and CI still runs the checks. A release no longer costs a run of the checks.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

tool/src/release/release_push.dart

@@ -0,0 +1,46 @@
+/// Whether a push to main brings release commits alone, which the pre-push
+/// hook then lets through without the checks (tool/check.dart): a release
+/// commit changes an app's version and adds its texts of what's new, nothing
+/// the checks look at, as the release tool already holds when it asks CI
+/// about the newest commit that isn't one (decided 3 Nov 2026, so that
+/// releases in a row don't run the checks once each).
+library;
+
+import 'version.dart';
+
+final _subject = RegExp(r'^chore\(release\): [a-z]+-v\d+\.\d+\.\d+$');
+final _file = RegExp(
+  '^apps/[a-z]+/halkyon_[a-z]+_flutter/'
+  r'(pubspec\.yaml|assets/whats_new/\d+\.\d+\.\d+\.[a-z]{2}\.txt)$',
+);
+final _versionLine = RegExp(r'^[+-]version: \d+\.\d+\.\d+\+\d+$');
+
+/// Why [commit] isn't a release commit, or null when it is one: its subject
+/// the release tool's, its files an app's pubspec and texts of what's new
+/// alone, and [pubspecLines], the lines its pubspecs' diff adds and removes
+/// (`+…`, `-…`), the version's alone.
+String? releaseCommitProblem(Commit commit, List<String> pubspecLines) {
+  if (!_subject.hasMatch(commit.subject)) {
+    return "${commit.subject}: not the release tool's subject.";
+  }
+  if (commit.files.isEmpty) {
+    return '${commit.subject}: changes no file.';
+  }
+  for (final file in commit.files) {
+    if (!_file.hasMatch(file)) {
+      return '${commit.subject}: changes $file.';
+    }
+  }
+  for (final line in pubspecLines) {
+    if (!_versionLine.hasMatch(line)) {
+      return '${commit.subject}: changes a pubspec beyond its version: $line';
+    }
+  }
+  return null;
+}
+
+/// Whether [commits], each with its pubspecs' changed lines, are some, and
+/// every one of them a release commit.
+bool onlyReleaseCommits(List<(Commit, List<String>)> commits) =>
+    commits.isNotEmpty &&
+    commits.every((entry) => releaseCommitProblem(entry.$1, entry.$2) == null);

tool/src/release/targets.dart

@@ -0,0 +1,59 @@
+/// The apps one run of the release tool releases, as its command line names
+/// them: `learn`, `train minor` (as always), or several in a row,
+/// `train:minor learn`, released one after another in that order.
+library;
+
+import 'version.dart';
+
+/// An app to release, and the version asked for, if any.
+final class const ReleaseTarget(final String app, [final Bump? chosen]) {
+  @override
+  bool operator ==(Object other) =>
+      other is ReleaseTarget && other.app == app && other.chosen == chosen;
+
+  @override
+  int get hashCode => Object.hash(app, chosen);
+
+  @override
+  String toString() => chosen == null ? app : '$app:${chosen!.name}';
+}
+
+/// The apps [words] name, of [apps], each with its version if asked for:
+/// after a colon (`train:minor`) or as the word after it (`train minor`).
+/// Throws a [FormatException] saying what is wrong otherwise.
+List<ReleaseTarget> parseTargets(List<String> words, Set<String> apps) {
+  final bumps = Bump.values.asNameMap();
+  final targets = <ReleaseTarget>[];
+  for (final word in words) {
+    if (bumps[word] case final bump?) {
+      final last = targets.lastOrNull;
+      if (last == null || last.chosen != null) {
+        throw FormatException('$word: which app?');
+      }
+      targets[targets.length - 1] = ReleaseTarget(last.app, bump);
+      continue;
+    }
+    final [app, ...rest] = word.split(':');
+    if (!apps.contains(app)) {
+      throw FormatException('No app "$app": one of ${apps.join(', ')}.');
+    }
+    if (targets.any((target) => target.app == app)) {
+      throw FormatException('$app is named twice.');
+    }
+    switch (rest) {
+      case []:
+        targets.add(ReleaseTarget(app));
+      case [final name] when bumps[name] != null:
+        targets.add(ReleaseTarget(app, bumps[name]));
+      default:
+        throw FormatException(
+          '$word: the version after the colon is none of major, minor, '
+          'patch.',
+        );
+    }
+  }
+  if (targets.isEmpty) {
+    throw const FormatException('No app named.');
+  }
+  return targets;
+}