test: add App integration tests covering state machine and keybindings

16 tests across 7 groups: happy path, ESC abort, error states, retry,
result keybindings (copy/chat/discard), slash commands, provider fallback.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: asanmateu

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- App integration tests covering state machine transitions, keybindings, abort handling, and provider fallback
 - GitHub URL support: blob URLs (`github.com/.../blob/...`) now fetch raw file content directly instead of scraping GitHub's HTML page
 - TTS provider abstraction: choose between Edge TTS (free, default) and OpenAI TTS (high quality, requires `OPENAI_API_KEY`)
 - `tts-provider` config key: `tldr config set tts-provider openai` / `edge-tts`