feat: release notes

Each release can carry notes in Markdown, written before or after it
ships. A draft is generated from its finished tickets grouped by type, to
edit and copy from the releases page.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

libs/api/tracker/application/src/lib/commands/command-handlers.ts

@@ -30,6 +30,7 @@ import { DetachFileCommandHandler } from './detach-file.command-handler';
 import { WatchIssueCommandHandler } from './watch-issue.command-handler';
 import { SetIssueParentCommandHandler } from './set-issue-parent.command-handler';
 import { RankIssueCommandHandler } from './rank-issue.command-handler';
+import { WriteReleaseNotesCommandHandler } from './write-release-notes.command-handler';
 import { SPRINT_COMMAND_HANDLERS } from './sprint.command-handlers';
 import { DetachFromParentCommandHandler } from './detach-from-parent.command-handler';
 import {
@@ -72,6 +73,7 @@ export const COMMAND_HANDLERS = [
   WatchIssueCommandHandler,
   SetIssueParentCommandHandler,
   RankIssueCommandHandler,
+  WriteReleaseNotesCommandHandler,
   ...SPRINT_COMMAND_HANDLERS,
   AddChecklistItemCommandHandler,
   UpdateChecklistItemCommandHandler,