Halkyon's shared packages

A pub workspace of the Dart packages Halkyon's apps share: halkyon_ui,
Halkyon's look (the theme, fonts, layout and shared widgets, with texts
in English and German), halkyon_core's low-level primitives and
halkyon_interop's cross-app contracts. Dart 3.13 with LeanCode's lints,
configured once at the root; apps take a package by git, pinned to a
signed commit.

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

pubspec.yaml

@@ -0,0 +1,15 @@
+name: _halkyon_shared_workspace
+publish_to: none
+
+environment:
+  sdk: ^3.13.0
+
+workspace:
+  - packages/halkyon_core
+  - packages/halkyon_interop
+  - packages/halkyon_ui
+  - packages/halkyon_ui/example
+
+dev_dependencies:
+  # Referenced by analysis_options.yaml in this directory.
+  leancode_lint: ^27.0.0