[codex] Add agent loop edit composer

[brsbl]

Summary

• Replaces the AGENT loop edit textarea with a prompt-box composer built from useComposerArea parts.
• Adds an automation-edit prompt draft scope and seeds it from the saved loop prompt whenever edit mode opens.
• Keeps SCRIPT loop editing on the existing monospace script/interpreter/timeout form.
• Adds a regression test for saving edited prompt/provider/model/permission into UpdateAutomationRequest.

Save Mapping

On AGENT loop save, the form sends:

• execution.mode: "agent"
• execution.prompt: composer.message
• execution.providerId: threadCreationOptions.selectedProviderId
• execution.model: threadCreationOptions.selectedModel
• execution.permissionMode: threadCreationOptions.permissionMode

name, trigger.cron, trigger.timezone, and autoArchive continue to come from the existing edit form state.

Validation

• pnpm exec turbo run typecheck --filter=@bb/app
• pnpm exec turbo run test --filter=@bb/app -- src/views/AutomationDetailView.test.tsx src/views/AutomationDetailView.script-edit.test.tsx src/views/AutomationDetailView.agent-edit.test.tsx src/components/secondary-panel/SideChatTabContent.test.tsx src/views/RootComposeView.test.ts src/views/RootComposeSecondaryContent.test.tsx src/views/RootComposeMobileRecents.test.tsx src/views/root-compose-branch-selection.test.ts src/views/root-compose-branch-ui.test.ts src/views/root-compose-thread-environment.test.ts
• pnpm exec turbo run test --filter=@bb/app -- src/hooks/usePromptDraftStorage.test.tsx

[brsbl]

Folded into #354 — the Add agent loop edit composer commit was merged into bb/redesign-thread-p-thr_xnwqkhbpc4 (merge commit 55f5e12f8), alongside resolving #354's conflicts with main. Closing this in favor of #354. Tests pass: AutomationDetailView.agent-edit + usePromptDraftStorage (9 app tests) and full-repo typecheck/lint.