refactor App into reusable components

[binhonglee]

most of these can be reused for the replay app on next PR

[codecov]

Codecov Report

❌ Patch coverage is 89.24731% with 10 lines in your changes missing coverage. Please review.
✅ Project coverage is 88.15%. Comparing base (50d6b2e) to head (b5761b0).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
components/LogList.tsx	62.50%	6 Missing and 3 partials ⚠️
hooks/useSplitPane.ts	96.66%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main       #8      +/-   ##
==========================================
+ Coverage   86.44%   88.15%   +1.71%     
==========================================
  Files           4        9       +5     
  Lines          59      152      +93     
  Branches       19       44      +25     
==========================================
+ Hits           51      134      +83     
- Misses          3        9       +6     
- Partials        5        9       +4     

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