Add scrollbar visibility improvements and beads sync

[Gabko14]

Summary

• Add GhostlyModifiers.swift with scrollbar visibility behavior for the editor
• Update beads gitignore with merge artifact patterns
• Sync beads issue data

Test plan

• Verify scrollbar appears on hover/scroll in editor
• Confirm no regressions in existing editor behavior

[claude]

PR Review

Critical Issues

1. NSViewRepresentable violates project conventions

The CLAUDE.md explicitly states:

Native SwiftUI components (no NSViewRepresentable wrappers)

This PR introduces TextEditorScrollbarBehavior: NSViewRepresentable which goes against the established architecture. If custom scrollbar behavior is needed, consider alternative approaches that stay within SwiftUI.

2. No tests provided

Per CLAUDE.md:

Nothing ships without automated tests. Before creating a PR, you must: 1. Write unit tests for all logic/model changes

This PR adds 241 lines of new logic but no tests. The scrollbar coordinator has testable logic (e.g., canScrollVertically, the observer setup/teardown, fade timing).

Other Concerns

3. Unrelated changes bundled together

The PR mixes two unrelated concerns:

• Scrollbar visibility improvements (the feature)
• .beads/.gitignore reorganization (tooling)

These should be separate commits or PRs for cleaner history and easier review.

4. Complexity for the use case

The implementation is ~240 lines of AppKit interop code that:

• Walks the view hierarchy to locate NSScrollView
• Sets up multiple NotificationCenter observers
• Manually manages observer lifecycle
• Uses DispatchWorkItem for fade debouncing

This adds significant maintenance burden. Is the native scrollbar behavior insufficient? What specific problem does this solve?

5. No linked issue

Without a linked issue, it's unclear what problem this solves or what the acceptance criteria are.

Code Quality Notes

The implementation itself is well-structured:

• Proper weak references to avoid retain cycles
• Clean observer cleanup in detachObservers()
• @MainActor annotations are correct
• Animation context usage is appropriate

Recommendation

Address the convention violations before merging:

1. Either get approval to deviate from "no NSViewRepresentable" convention, or find an alternative approach
2. Add unit tests for the coordinator logic
3. Split unrelated .beads/ changes into a separate PR