Add ScrollInterCeptionBehavior for toggling autoscroll

[nz366]

Summary

Briefly describe what this PR changes and why.

• Motivation / Context: With current implementation scroll interceptor does not work with trackpads. So chrome like auto-scroll was added.

Type of change

• [ ] fix: Bug fix (non-breaking change)
• [x] feat: New feature / new component
• [ ] perf: Performance improvement
• [ ] refactor/chore: Code refactor or tooling update
• [ ] docs: Documentation only
• [ ] build/devtools: Generators, scripts, or infra changes

Scope (check all that apply)

• [x] Components (lib/src/components/...)
• [ ] Utilities (lib/src/util.dart, animation/collection, platform)
• [ ] Icons / Fonts (icons/, lib/icons/, pubspec fonts)
• [ ] Theme / Colors (lib/src/theme/, colors/ + style transpilers)
• [x] Docs app (docs/)
• [ ] Generators / Tools (gen/bin/)
• [ ] Example app (example/)
• [ ] Tests (example/test/, test_widget/)
• [ ] CI / Workflows

Linked issues

Closes # Refs #

Screenshots / Videos (if UI)

Include light/dark and relevant states.

Breaking changes

• [ ] Yes (add migration notes below)
• [x] No

How I tested

• Manual verification in docs app (Chrome)

Checklist

Please ensure the following are complete before requesting review. See CONTRIBUTING.md for details.

• [x] Code formatted (dart format .)
• [x] Analyzer passes (flutter analyze)
• [ ] Tests added/updated and passing (flutter test where applicable)
• [ ] Public API documented (public_member_api_docs)
• [ ] Docs/examples updated (docs pages or README images)
• [ ] Exports updated in lib/shadcn_flutter.dart (for new public widgets)
• [ ] A11y validated in docs (run_docs_web_semantics.bat)
• [ ] Generators run when relevant:
  • [ ] LLMs / Guides (gen_dotguides.bat)
• [ ] CHANGELOG updated (if user-visible change)

Additional notes

[nz366]

Turns out chrome supports both drag scrolling and tap scrolling. Should I remove the Behavior class then or add extra configuration?

[sunarya-thito]

Turns out chrome supports both drag scrolling and tap scrolling. Should I remove the Behavior class then or add extra configuration?

Whats the extra configuration?

[nz366]

Turns out chrome supports both drag scrolling and tap scrolling. Should I remove the Behavior class then or add extra configuration?

Whats the extra configuration?

switch between hold or tap scrolling (current) final bool holdDrag; extra config that enables combined hold drag + move / tap release to activate scrolling (default chrome behavior)

final bool holdDragOrTap;

Could be a new Enum

or just remove behavior class so when enabled it works in that holdDragOrTap combined interaction.

[sunarya-thito]

I couldn't picture what youre describing, try it out, ill leave feedback later.