feat(publish): releases in git (public tier, stage 2)

A person with an identity and a public profile publishes a studyset with
everything inside it as its next release (ADR 0005, rule 3): the server
reads their synced rows and writes them through the git command as a
commit on main and the annotated tag vN, in a bare repository of the
studyset's own, named by a random public id made at the first publish.

A release is a directory per studyset with a file per card, note, path,
step and PDF (its id, position, tag names and payload as synced, keys
sorted and indented) and the files the content names, without what is
only the author's (a card's report, a PDF's deadline). Publishing is
refused without a licence allowing passing it on in every studyset ("no
derivatives" allowed), with revisions to settle, with files not uploaded
yet, when nothing changed, or for a name that won't do; the name is
fixed from the first release, as is the person's handle.

In the app, Share in a studyset's action row opens the Publish sheet;
publishing syncs first, and settles by itself the revisions that merge
cleanly, listing only real conflicts. The server's image gets git, the
repositories a volume of their own, and the hourly backup a git bundle of
each.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MMm7usAo6q9ZZRoPkWjoxi
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

halkyon_learn_flutter/lib/l10n/app_localizations_en.dart

@@ -4998,6 +4998,151 @@ class AppLocalizationsEn extends AppLocalizations {
     );
     return '$_temp0';
   }
+
+  @override
+  String get studysetShare => 'Share';
+
+  @override
+  String get studysetSharePrivate => 'Share: private';
+
+  @override
+  String get studysetSharePublished => 'Share: published';
+
+  @override
+  String get publishTitle => 'Publish';
+
+  @override
+  String get publishPrivate => 'Private · only you can see it';
+
+  @override
+  String publishPublished(int version, String date) {
+    return 'Published · v$version · $date';
+  }
+
+  @override
+  String get publishIntro =>
+      'A release is this studyset with everything inside it, as it is now. Others can find it, learn from it and copy it. Each release stays as it was; later changes go into the next one.';
+
+  @override
+  String get publishAnonymous =>
+      'Sign in with GitHub to have a public profile and publish.';
+
+  @override
+  String get publishName => 'Name';
+
+  @override
+  String get publishNameHint => 'japanese';
+
+  @override
+  String publishLocation(String location) {
+    return 'Found at $location';
+  }
+
+  @override
+  String get publishNameFixed =>
+      'Fixed since you first published: others refer to it.';
+
+  @override
+  String get publishLicence => 'Licence';
+
+  @override
+  String get publishLicenceNone => 'None';
+
+  @override
+  String get publishLicenceOpen => 'Allows publishing.';
+
+  @override
+  String get publishLicenceNoDerivatives =>
+      'Allows publishing as it is: learners keep their changes to themselves.';
+
+  @override
+  String get publishLicenceClosed =>
+      'Doesn\'t allow passing it on. Choose another under Edit.';
+
+  @override
+  String publishLicenceNotOpen(String titles) {
+    return 'These studysets\' licences don\'t allow passing them on: $titles';
+  }
+
+  @override
+  String get publishNotes => 'What changed';
+
+  @override
+  String get publishNotesHint => 'New in this release…';
+
+  @override
+  String get publishReleases => 'Releases';
+
+  @override
+  String publishRelease(int version, String date) {
+    return 'v$version · $date';
+  }
+
+  @override
+  String publishButton(int version) {
+    return 'Publish v$version';
+  }
+
+  @override
+  String get publishNoProfile =>
+      'A release names you by your public profile. Make one first.';
+
+  @override
+  String get publishMakeProfile => 'Make a public profile';
+
+  @override
+  String get publishConflicts =>
+      'These were changed differently on two devices. Settle them first:';
+
+  @override
+  String get publishConflictsElsewhere =>
+      'Some cards, notes or steps were changed differently on two devices. Sync, then try again.';
+
+  @override
+  String get publishUntitled => 'Untitled';
+
+  @override
+  String get publishFilesMissing =>
+      'Some files haven\'t reached your instance yet. Try again in a moment.';
+
+  @override
+  String get publishNothingChanged =>
+      'Nothing has changed since the last release.';
+
+  @override
+  String get publishBusy =>
+      'This studyset is being published already. Try again in a moment.';
+
+  @override
+  String get publishSlugInvalid =>
+      'Lower-case letters, digits and hyphens, starting with a letter or digit.';
+
+  @override
+  String get publishSlugTaken => 'Another of your studysets has this name.';
+
+  @override
+  String get publishNotesTooLong => 'At most 5,000 characters.';
+
+  @override
+  String publishDone(int version) {
+    return 'Published v$version.';
+  }
+
+  @override
+  String get publishFailed =>
+      'Couldn\'t reach your instance. Nothing was published.';
+
+  @override
+  String get publishUnreachable => 'Publishing can\'t be reached right now.';
+
+  @override
+  String get publishRetry => 'Retry';
+
+  @override
+  String get publishCopyLocation => 'Copy address';
+
+  @override
+  String get publishLocationCopied => 'Address copied.';
 }
 
 /// The translations for English, as used in the United Kingdom (`en_GB`).
@@ -5075,4 +5220,12 @@ class AppLocalizationsEnUs extends AppLocalizationsEn {
 
   @override
   String get homeCustomise => 'Customize';
+
+  @override
+  String get publishLicence => 'License';
+
+  @override
+  String publishLicenceNotOpen(String titles) {
+    return 'These studysets\' licenses don\'t allow passing them on: $titles';
+  }
 }