feat: add tree node properties

[hunjixin]

No description provided.

[hunjixin]

#47

[codecov]

Codecov Report

Merging #49 (0cef941) into main (b3ec816) will increase coverage by 2.04%.
Report is 1 commits behind head on main.
The diff coverage is 76.25%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #49      +/-   ##
==========================================
+ Coverage   56.34%   58.39%   +2.04%     
==========================================
  Files          71       82      +11     
  Lines        7191     7970     +779     
==========================================
+ Hits         4052     4654     +602     
- Misses       2691     2810     +119     
- Partials      448      506      +58     

Files	Coverage Δ
versionmgr/changes.go	70.44% <ø> (ø)
versionmgr/commit.go	65.34% <100.00%> (+0.39%)	⬆️
versionmgr/merkletrie/internal/frame/frame.go	100.00% <100.00%> (ø)
versionmgr/merkletrie/internal/fsnoder/dir.go	100.00% <100.00%> (ø)
versionmgr/merkletrie/internal/fsnoder/file.go	100.00% <100.00%> (ø)
versionmgr/tree_node.go	74.24% <100.00%> (-1.57%)	⬇️
versionmgr/worktree.go	61.90% <100.00%> (-1.72%)	⬇️
versionmgr/merkletrie/noder/path.go	97.72% <97.72%> (ø)
models/repo.go	70.00% <66.66%> (-3.08%)	⬇️
auth/session_store.go	0.00% <0.00%> (ø)
... and 11 more

... and 1 file with indirect coverage changes