release v2.3.0

Cut the accumulated Unreleased entries under a dated 2.3.0 heading and
bump pubspec + licenses self.version. Minor bump: the batch adds features
(file references, task dock, deny-simplify, ticket pick-up, type-filter
chips, VS Code/JetBrains keymaps) alongside the fixes.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

assets/licenses.yaml

@@ -39,7 +39,7 @@ self:
   # Auto-synced from pubspec.yaml `version:` by `make gen-build-info`
   # (runs implicitly on every build/run/test). Don't hand-edit; bump
   # pubspec instead.
-  version: "2.2.0"
+  version: "2.3.0"
   homepage: https://github.com/postmeridiem/clide
   license: MIT
   license_file: assets/LICENSE