feat(app): add auto-review flow and model preferences

[dzianisv]

Summary

• add auto-review controls in the prompt and command palette, including toasts and persisted settings state
• add Models settings for default model, review model, and auto-review toggle, and wire default model into local model resolution
• auto-queue a review follow-up after completed assistant turns using the configured review model, with loop-avoidance guards and xhigh when supported
• add e2e selectors and settings tests for model preference persistence and prompt/settings auto-review toggle sync
• add AGENTS note that isolated app e2e specs should run via bun test:e2e:local -- -- <spec>

Validation

• bun typecheck (packages/app)
• bun test (packages/app)
• bun test:e2e:local -- -- e2e/settings/settings-models.spec.ts
• pre-push bun turbo typecheck hook passed during push

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