fix: update flutter packages (#148) (#165)
## Summary
- Upgrades 9 direct dependencies and their transitive peers to resolve the CI warning: *"38 packages have newer versions incompatible with dependency constraints"*
- Reduces incompatible-version count from **38 → 21** (the remaining 21 are either deliberately pinned, constrained by transitive dep ceilings, or require a separate riverpod 2→3 migration)
- Adapts two source files to breaking API changes in the upgraded packages:
- `notification_service.dart`: `flutter_local_notifications` 21.x changed positional args to named params (`initialize(settings:…)`, `show(id:…, title:…, body:…, notificationDetails:…)`)
- `compose_screen.dart`: `file_picker` 12.x removed `FilePicker.platform` static getter; calls are now `FilePicker.pickFiles()`
## Packages changed
| Package | Before | After |
|---|---|---|
| `go_router` | ^14.8.1 | ^17.2.3 |
| `flutter_local_notifications` | ^18.0.1 | ^21.0.0 |
| `file_picker` | ^8.0.0 | ^12.0.0-beta.4 |
| `mobile_scanner` | ^5.0.0 | ^7.2.0 |
| `package_info_plus` | ^8.0.0 | ^10.1.0 |
| `share_plus` | ^12.0.2 | ^13.1.0 |
| `sqlite3_flutter_libs` | ^0.5.28 | ^0.6.0+eol |
| `flutter_lints` | ^4.0.0 | ^6.0.0 |
| `flutter_secure_storage` | 10.2.0 | 10.3.0 (patch) |
## Test plan
- [x] `flutter analyze` — no issues
- [x] Unit tests (324 passed)
- [x] Widget tests (116 passed)
- [ ] CI full check suite
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-authored-by: Thomas SharedInbox <sharedinbox@thomas-guettler.de>
Reviewed-on: https://codeberg.org/guettli/sharedinbox/pulls/165
