Add safety regression tests and CI

[flandyw]

Stacked on PR #2 for a focused review diff.

Changes:

• replaces the unused Flutter counter-template test with real screen smoke tests
• adds fake ProcessRunner-based tests for ADB device parsing and serial scoping
• adds Fastboot getvar/device/serial-scoping tests
• tests backup-manifest round-tripping and corruption detection
• validates manifest partition names, image basenames, sizes, SHA-256 values, serial presence and duplicate entries before restore
• updates the desktop dependency chain to a modern file_picker release compatible with current Flutter/Dart while retaining the existing picker API
• adds GitHub Actions for flutter analyze + flutter test
• fixes the production MaterialApp title
• updates the README to document the verified backup/restore safety model and destructive-action requirements

Validation: the combined stack passes flutter pub get, flutter analyze, and flutter test in GitHub Actions.

Merge workflow: merge PR #1 into master, retarget/merge PR #2 to master, then retarget this PR from fix/restore-safety to master before merging it.

[coderabbitai]

Important

Review skipped

Auto reviews are disabled on base/target branches other than the default branch.

Please check the settings in the CodeRabbit UI or the .coderabbit.yaml file in this repository. To trigger a single review, invoke the @coderabbitai review command.

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: f9dc72cc-fbf9-46a3-a53a-af4141054cc5

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

Use the checkbox below for a quick retry:

• 🔍 Trigger review

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}