feat: add Memory event TUI

[notgitika]

This PR adds TUI implementation to the memory event list and get commands implemented in PR #1895

The flow:
Memory -> Actor -> Session -> Event selection

It lists events with branch and occurrence time and opens up selected event as an entire JSON. Pagination, filtering, retries, empty states, and back navigation is implemented.

I had to add internal read-only Actor and Session listing APIs, which we could as future work make into their own commands.

I tested myself + using the TUI harness skill.

Typcheck, lint, build and test passes

[codecov-commenter]

Codecov Report

❌ Patch coverage is 98.96907% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 96.14%. Comparing base (ae6a526) to head (8e64c48).

Files with missing lines	Patch %	Lines
src/handlers/memory/event/list/screen.tsx	98.73%	2 Missing ⚠️
src/handlers/memory/event/screen.tsx	50.00%	1 Missing ⚠️

Additional details and impacted files

@@                        Coverage Diff                         @@
##           feat/memory-events-records-cli    #1906      +/-   ##
==================================================================
+ Coverage                           96.08%   96.14%   +0.05%     
==================================================================
  Files                                 231      235       +4     
  Lines                               11569    11821     +252     
==================================================================
+ Hits                                11116    11365     +249     
- Misses                                453      456       +3     

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