fix(cli): stop claiming that accept merges anything

`mcpctl tasks accept --help` said "fires the merge". Nothing merges. There is
no createPullRequest or mergePullRequest anywhere in the codebase — the
git-provider client is task 148 and is not built.

Accept records human approval and moves the task to `merged`. Until 148/149
land, `merged` means "a human approved this", not "this is in main", and the
help text and service comments now say so. A user who accepted a task expecting
a PR to land would have been silently wrong.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/cli/src/commands/tasks.ts

@@ -85,7 +85,7 @@ export function createTasksCommand(deps: TasksCommandDeps): Command {
     });
 
   cmd.command('accept')
-    .description('Accept a task awaiting review — fires the merge')
+    .description('Accept a task awaiting review (records the decision; does NOT merge the PR yet)')
     .argument('<task>', 'Task name or id')
     .option('--note <text>', 'Comment stored with the decision')
     .action(async (task: string, opts) => {