Fix plan command support in web bridge (#1018)

* fix: support plan command in web bridge

* fix: preserve queued bridge messages

* fix: avoid duplicate queued plan messages

* fix: preserve plan command semantics

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Co-authored-by: Codex <codex@openai.com>

packages/client/src/i18n/locales/en.ts

@@ -219,6 +219,7 @@ export default {
       status: 'Show session status and queue',
       abort: 'Stop the active bridge run',
       queue: 'Queue a message behind the active run',
+      plan: 'Write a markdown implementation plan',
       clear: 'Clear the current display',
       clearHistory: 'Delete this session’s stored message history',
       title: 'Rename this session',